li^iyjylLii'.^ 


UL^U  \i'^   li    oU 


THE    PREVENTION    OF    MALARIA 


PRESENTED   TO   HIS   MAJESTY  THE   KING 
BY 

HER    ROYAL   HIGHNESS   PRINCESS   CHRISTIAN 

Honorary  President 
Liverpool  School  of  Tropical  Medicine 


THE    PREVENTION 
OF    MALARIA 


BY    RONALD    ROSS, 

D.P.H.,  F.R.C.S.,  D.Sc,  LL.D.,  F.R.S.,  C.B. 
NOBEL    LAUREATE 


WITH   CONTRIBUTIONS   BY 


Professor     L.     O.    HOWARD, 

United  States 
Colonel  W.  C.  GORGAS,  Panama 
Mr  J.  A.  LE  PRINCE,  Panama 
Sir  R.  BOYCE,  West  Indies 
Dr  W.  T.  PROUT,  Jamaica 
Dr  H.  WOLFERSTAN  THOMAS, 

Amazon  Region 
Dr    OSWALDO    CRUZ,    South 

Brazil 
Dr  IAN  MACDONALD,  Spain 
Professor  A.  CELLI,  Italy 
Professor  C.  SAVAS,  Greece 


Professor    C.    SCHILLING, 

German  Possessions 
Dr    ED.     SERGENT,     French 

Possessions 
Mr  H.  C.  ROSS,  Egypt 
Dr  a.  BALFOUR,  Khartum 
Dr  L.  BOSTOCK,  South  Africa 
Dr  P.  MURISON,  Durban 
Dr  M.  WATSON,  Malay  States 
Professor  T.  TAKAKI,  Formosa 
Colonel     C.      H.     MELVILLE, 

Troops  in  War 
Major    C.      E.     P.      FOWLER, 

Troops  in  Peace 


WITH    MANY   ILLUSTRATIONS 


NEW  YORK 
E.   P.    BUTTON   &   COMPANY 

1910 


?UBLI    : 

HEALTH  . 
LIBRARY 


PREFACE 

Malarial  fever  is  perhaps  the  most  important  of  human 
diseases.  Though  it  is  not  often  directly  fatal,  its  wide 
prevalence  in  almost  all  warm  climates  produces  in  the 
aggregate  an  enormous  amount  of  sickness  and  mortality. 
In  India  alone  it  has  been  officially  estimated  to  cause 
a  mean  annual  death-rate  of  five  per  thousand ;  that 
is,  to  kill  every  year  on  the  average  1,130,000  persons 
— a  population  equal  to  that  of  a  great  city.  This  is 
more  than  the  mortality  of  plague  at  its  height  or  of 
cholera  and  dysentery  combined.  The  total  amount 
of  sickness  due  to  it  is  incalculable,  but  may  be  put 
by  a  rough  estimate  at  between  a  quarter  and  a  half 
the  total  sickness  in  many  tropical  countries.  Often 
all  the  children  and  most  of  the  adults  are  infected  by 
it.  Unlike  many  epidemic  diseases  it  is  not  transient, 
but  remains  for  ever  in  the  areas  which  it  has  once 
invaded.  It  tends  to  abound  most  in  the  most  fertile 
countries,  and  at  the  season  most  suitable  for  agricul- 
ture. Very  malarious  places  cannot  be  prosperous  :  the 
wealthy  shun  them  ;  those  who  remain  are  too  sickly  for 
hard  work;  and  such  localities  often  end  by  being  deserted 
by  all  save  a'  few  miserable  inhabitants.  Malaria  is 
the  great  enemy  of  the  explorer,  the  missionary,  the 
planter,    the    merchant,    the    farmer,    the    soldier,    the 

vii 


215031 


viii  PREFACE 

administrator,  the  villager  and  the  poor ;  and  has,  I 
believe,  profoundly  modified  the  world's  history  by 
tending  to  render  the  whole  of  the  tropics  comparatively 
unsuitable  for  the  full  development  of  civilisation.  It  is 
essentially  a  political  disease — one  which  affects  the  wel- 
fare of  whole  countries  ;  and  the  prevention  of  it  should 
therefore  be  an  important  branch  of  public  adminis- 
tration. For  the  State  as  for  the  individual,  health  is 
the  first  postulate  of  prosperity.  And  prosperity  should 
be  the  first  object  of  scientific  government. 

Fortunately,  as  often  remarked,  malaria  is  of  all 
diseases  the  one  regarding  which  we  possess  perhaps 
the  fullest  knowledge.  We  know  the  cause  of  it  and 
the  manner  in  which  it  is  spread.  We  know  a  specific 
cure  for  it,  and  several  efficient  methods  of  prevention. 
It  is  our  own  fault  then  if  we  do  not  reduce  it  as  much 
as  possible. 

The  literature  of  the  subject  dates  back  for  more 
than  two  thousand  years.  To  write  a  complete  book 
on  malaria,  including  references  to  all  that  has  been 
worthily  said  or  done  in  connection  with  it,  would  be 
a  gigantic  task.  The  history,  the  symptoms,  the 
pathology  and  the  treatment  would  fill  several  volumes  ; 
a  long  essay  could  be  written  on  the  parasites ;  an 
entomological  work  on  their  carriers ;  and  a  full  account 
of  the  laws  of  diffusion,  of  the  local  distribution,  of  the 
preventive  measures,  and  of  the  numerous  preventive 
campaigns  which  have  been  conducted  since  the  time 
of  the  ancients,  would  of  itself  occupy  many  hundreds 
of  pages.  But  the  task  would  be  largely  an  unnecessary 
one,  because  we  already  possess  many  good  books  on 


PREFACE  ix 

the  medical,   parasitological  and  entomological  aspects 
of  the  subject. 

Regarding  prevention,  however,  especially  in  the 
light  of  the  great  developments  which  followed  the 
discoveries  of  twelve  years  ago,  there  is  much  need 
for  yet  another  work.  Though  certainly  based  upon 
biological  knowledge,  this  part  of  the  subject  presents 
also  its  own  problems  for  solution.  The  diffusion  of 
disease  is  a  theme  which  requires  exact,  and  indeed 
mathematical  analysis ;  and  the  art  of  controlling  it 
belongs,  not  only  to  the  medical  man,  the  parasitologist 
and  the  entomologist,  but  even  more  to  the  experienced 
hygienist,  the  engineer,  the  administrative  officer  and 
the  statesman. 

On  considering  how  best  to  meet  the  demand,  I 
concluded  that  the  only  satisfactory  way  was  to  collect 
in  one  volume  the  thoughts  and  observations  of  the 
able  men  who  have  themselves  worked  in  this  laborious 
field,  or  who  are  in  the  best  position  to  furnish  the 
required  information  ;  and  my  warmest  thanks  are  due 
to  those  who  have  given  me  so  much  of  their  valuable 
time  and  labour.  My  own  part  consisted  merely  in 
attempting  to  compile  a  preliminary  analysis  of  the 
general  problems  and  difficulties  before  us. 

Some  readers  will  perhaps  be  surprised  when  they 
fail  to  find  in  a  book  on  the  prevention  of  malaria  any 
description  either  of  the  parasites  and  their  carriers,  or 
of  the  necessary  technique.  But  in  these  days  almost 
every  medical  man  in  the  tropics,  at  least  any  one  likely 
to  be  entrusted  with  the  charge  of  anti-malaria  work, 
is  sure  to  be  already  familiar  with  these  details.     More- 


X  PREFACE 

over,  the  present  volume  should  be  written  largely  for 
the  use  of  readers  who  are  neither  medical  men  nor 
zoologists,  but  who  may  be  called  upon  to  deal  with 
the  administrative  side  of  the  subject ;  and  minute 
technicalities  would  be  as  useless  to  them  as  they  would 
be  superfluous  to  the  trained  biologist.  I  have  there- 
fore determined  to  limit  myself  to  matters  which  will,  I 
hope,  be  useful  to  the  advanced  student  without  being 
unintelligible  to  any  educated  reader  —  that  is,  to  a 
logical  consideration  of  the  broader  (and  often  more 
neglected)  principles  of  the  subject. 

An  historical  introduction  is  always  necessary  to  give 
coherence  to  ideas ;  and  I  have  taken  the  opportunity 
to  write  as  complete  and  accurate  a  one  as  my  space 
and  knowledge  permit  of.  The  summary  of  facts  which 
follows  (taken  from  my  report  on  Mauritius)  may  be 
useful  in  propagandism ;  the  experimental  inoculations 
of  men  by  means  of  blood  drawn  from  patients  or  of 
infected  Anophelines  have  been  collected  with  care 
because  of  their  fundamental  importance  in  the  modern 
theory  of  malaria ;  and  I  trust  that  these  three  first 
chapters  will  suffice  to  convince  the  busy  layman  that 
this  theory  has  been  based  upon  something  more  than 
mere  conjecture. 

In  the  chapters  on  the  parasitic  invasion  of  the 
individual  and  of  the  community,  I  have  departed  con- 
siderably from  medical  custom  by  laying  much  stress 
upon  quantitative,  or  rather  enumerative,  ideas.  We 
should  distinguish  between  subscience,  the  mere  study 
of  objects,  and  science,  the  study  of  causes.  Measure- 
ment is  the  very  basis  of  science ;  and  the  neglect  of 


PREFACE  xi 

it  and  of  logical  deductions  founded  upon  it  are  too 
common  in  biology.  It  is  scarcely  true  to  say  that 
malarial  fever  is  caused  by  a  parasite  and  propagated 
by  a  mosquito  :  it  can  be  caused  only  by  many  parasites 
and  widely  propagated  only  by  many  mosquitos.  The 
how  much  and  the  how  many  are  at  least  as  important 
as  the  bare  facts.  I  am  convinced  that  if  more  exact 
results  are  desired,  pathology  must  in  the  future  tend 
more  toward  exact  enumerative  methods.  As  for 
epidemiology,  it  is  principally  a  mathematical  subject 
— the  route  of  infection  being  given,  the  rate  of  in- 
fection depends  upon  laws  like  those  which  govern  the 
diffusion  of  gases  or  heat ;  and  ignorance  of  this  has 
led  to  many  wild  statements  regarding  the  spread  and 
prevention  of  malaria.  But  the  subject  has  yet  to  be 
developed,  and  Chapter  V  can  approach  it  only  in  an 
elementary  manner.  Chapter  VI  is  abbreviated  owing 
to  the  details  contained  in  the  following  one,  to  which 
it  is  largely  introductory. 

The  contributions  in  Chapter  VII  are  arranged 
geographically,  as  far  as  possible,  and  have  been 
printed  in  the  authors'  words  without  modification.  A 
useful  index  has  been  found  impracticable  ;  but  a  detailed 
table  of  contents  is  given  at  the  end  of  the  volume. 

The  omission  of  several  important  matters  must  be 
explained  and  apologised  for.  Some  good  campaigns 
have  been  left  undescribed  because  I  could  not  find 
reporters  for  them  and  failed  in  obtaining  otherwise 
all  the  necessary  particulars  regarding  them ;  not  in 
any  way  because  they  should  not  have  been  included. 
A  chapter  on  the  local  distribution  and  cost  of  malaria 


xii  PREFACE 

would  have  been  useful,  and  was  attempted.  The  older 
books  contain  much  on  the  former  point  ;  but  the 
information  given  was  based  upon  evidence  which  would 
scarcely  satisfy  us  to-day,  and  accurate  details  could 
not  be  obtained  without  such  long  enquiry  that  I  was 
forced  to  abandon  the  project  entirely.  Lastly,  refer- 
ences to  much  good  literature  have  been  omitted  or 
curtailed — not  because  such  literature  is  of  secondary 
importance,  but  because  the  object  of  the  book  is  to 
present  a  general  discussion  of  particular  points  rather 
than  a  complete  record  of  all  the  known  facts  and 
hypotheses.  But  there  is  another  reason  for  these 
omissions.  Owing  to  grants  recently  given  by  the 
Advisory  Committee  for  the  Tropical  Diseases'  Re- 
search Fund  (collected  by  the  British  Colonial  Office), 
we  are  now  preparing  in  Liverpool,  not  only  for  new 
researches,  but  for  an  exhaustive  descriptive  biblio- 
graphy of  malaria,  in  which,  I  trust,  all  the  literature 
both  of  general  and  of  local  interest  will  be  collated 
and  compared.  Indeed  before  long  the  whole  of  this 
immense  subject  will  perhaps  be  dealt  with  in  the  only 
adequate  manner  possible — that  is,  by  a  special  Bureau 
appointed  for  the  study  of  it ;  and  this  book  is  intended 
to  be  a  necessary  preliminary  to  that  work. 

I  hope  that  most  of  the  matter  contained  in  it  will 
be  of  use  to  any  one  who  proposes  to  undertake  a  genuine 
campaign  against  malaria.  For  this  purpose  we  require 
a  knowledge,  not  only  of  biological  technics  and  of  the 
various  possible  preventive  measures,  but  also  of  the 
broad  principles  of  sanitary  statesmanship.  The  pre- 
vention of  malaria  on  a  large  scale  is  a  great  economical 


PREFACE  xiii 

as  well  as  a  great  humanitarian  undertaking.  A  genuine 
campaign  does  not  consist  merely  in  the  formation  of 
inexpert  committees,  the  passing  of  ordinances  for  the 
screening  of  water-butts,  and  the  issue  of  wise  advice 
to  the  public.  To  be  permanently  and  economically 
successful,  it  must  always  be  a  permanent  concern  of 
the  State,  requiring  careful  measurements  of  the  amount 
of  sickness  present,  a  nice  appreciation  of  the  measures 
most  suitable  for  the  locality,  exact  estimates  of  their 
cost  compared  with  the  cost  of  the  disease,  a  well- 
considered  organisation,  and,  above  all,  a  fixed  deter- 
mination to  succeed. 

The  world  requires  at  least  ten  years  to  understand 
a  new  idea,  however  important  or  simple  it  may  be. 
The  mosquito  theorem  of  malaria  was  at  first  ridiculed, 
and  its  application  to  the  saving  of  human  life  treated 
with  neglect,  jealousy  and  opposition.  But  now,  owing 
to  the  labours  of  many  of  those  who  have  contributed 
to  this  volume,  and  of  all  of  those  who  have  so  long 
and  so  patiently  studied  the  subject,  we  are  assured 
of  final  success.  To  them  and  to  the  memory  of  them 
this  book  is  dedicated  ;  but  we  must  not  rest  content 
until  the  principles  so  well  established  by  them  are 
followed  in  every  civilised  country  of  the  world.  I 
hope,  too,  that  mosquito  reduction  will  before  long  be 
undertaken  in  most  of  the  towns  in  the  tropics,  whether 
they  are  malarious  or  not. 

RONALD    ROSS. 


University  of  Liverpool 
\st June  igio. 


CONTENTS 


CHAP 

I. 

HISTORY 

Section 

I. 

2. 

)> 

3- 

)) 

4- 

Ancient  Times      .... 

Early  Modern  Times 

Discovery  of  the  Parasites 

Speculations  regarding  the  Mode  of  Infection 

5.  Researches  regarding  the  Mode  of  Infection 

6.  Confirmations  and  Extensions    . 

7.  Recent  History  of  Prevention 

8.  Remarks   ..... 


SUMMARY   OF   FACTS  REGARDING   MALARIA 

{Suitable  for  Public  Instruction) 

Section    9.  The  Parasites  and  the  Fever 
„       10.  The  Mode  of  Infection     . 
„       II.  Facts  about  Mosquitos     . 
„       12.  Personal  Prevention 
,,       13.  Public  Prevention 


III.  THE   FUNDAMENTAL  OBSERVATIONS  AND  EXPERIMENTS 

Section  14.  The  Parasites  cause  the  Disease 
„       15.  Experimental  Blood  Inoculations 
„       16.  The  Parasites  develop  in  Certain  Mosquitos 
„       17.  Experimental  Mosquito  Inoculations 

IV.  THE  PARASITIC   INVASION   IN   MAN      . 

Section  18.  The  Onset  of  the  Invasion 

„  19.  The  Further  Progress  of  the  Invasion   . 

„  20.  The  Decline  of  the  Invasion 

„  21.  Average  Duration  of  Untreated  Infections 

„  22.  Enlargement  of  the  Spleen  and  Liver    . 

„  23.  The  Effect  of  Quinine 

,,  24.  Summary  ..... 

XV 


PAGE 
I 

I 

6 

8 
10 
20 
26 
29 
43 

49 

49 

54  / 
58/ 
60 

62 

62 
66 

76    . 

77 

86 

86 

98 
104 
122 
127 
134 
143 


CONTENTS 


Section 

25. 

)) 

26 

?i 

27 

of 


CHAP. 

V.    MALARIA    IN   THE  COMMUNITY  .  .  .  . 

Is    the    Infection    caused    otherwise   than    by 

Anophelines  ? . 
Some  Definitions 
Conditions    required    for    the    Production 

New  Infections  in  a  Locality 

28.  Laws  which  Regulate  the  Amount  of  Malaria 
in  a  Locality  .... 

29.  Laws   which   Regulate  the   Number  of  Ano 
phelines  in  a  Locality 

30.  Explanation  of  Various  Phenomena 

31.  The  Measurement  of  Malaria 

32.  The  Mortality  and  Cost  of  Malaria 


PAGE 

145 


VI.    PREVENTION         ...... 

Section  33.  List  of  the  Possible  Preventive  Measures 
V 


for 


34.  Protection  against  the  Bites  of  Mosquitos 

35.  Mosquito-reduction 

36.  Prevention  by  Treatment 

37.  Selection     of    Measures 

Domestic  Prophylaxis 

38.  General  Sanitary  Axioms 

39.  Selection  of  Measures  for  Public 

40.  Conduct  of  the  Campaign 


VII.   SPECIAL   CONTRIBUTIONS 


Personal     and 


Prevention 


No.  of  Section. 

Contributor. 

Country. 

41 

Professor  Howard 

United  States 

,    42 

Colonel  Gorgas 

Panama 

V    43 

Mr  Le  Prince 

Panama 

44 

Sir  Rubert  Boyce 

West  Indies    . 

45 

Dr  Prout 

Jamaica 

46 

Dr  Wolferstan  Thomas 

Amazon  Region 

47 

Dr  Oswaldo  Cruz 

South  Brazil    . 

48 

Dr  MacDonald 

Spain    . 

49 

Professor  Celli 

Italy     . 

50 

Prof.  Dr  Savas 

Greece 

51 

Prof.  Dr  Schilling 

German  Possessions 

52 

Dr  Sergent 

French  Possessions 

53 

Mr  H.  C.  Ross 

Egypt  . 

54 

Dr  Balfour 

Khartoum 

CONTENTS 

xvii 

No.  of  Section.       Contributor 

Country 

PAGE 

55 

Dr  Bostock 

South  Africa 

543 

56 

Dr  Murison 

Durban     . 

549 

57 

Dr  Watson 

Malay  States 

554 

58 

Professor  Takaki 

Japan 

563 

59 

Professor  R.  Ross 

Other  Countries  . 

568 

60 

Colonel  Melville 

Troops  in  War    . 

577 

61 

Major  Fowler 

Troops  in  Peace 

600 

ADDENDA  .... 

621 

62 

Suggested  Terminology  for  the 

Phenomena  of  Cytogenesis 

621 

63 

Notes  on  the  Malaria-bearing  Anophelines   . 

622 

64 

Examples  of  Legislation 

636 

65 

Notes     .... 

638 

REFERENCES 

645 

CONTENTS   IN   DETAIL      . 

664 

LIST   OF    ILLUSTRATIONS 

NET     FOR     MEASURING     THE      OUTPUT     OF      MOSQUITOS 
FROM   A   MARSH — CLAIRFOND,   MAURITIUS. 

BANKS    OF    A    STREAM    ROUGH-TRAINED    FOR    RS.O-37    A 

RUNNING   FOOT   FOR   BOTH   BANKS   (MAURITIUS).        .     To  face  page  l66 

PLAN   OF  VACOAS  CAMP  AND  CLAIRFOND   MARSHES  .     To  face  page   l88 

FIG.  I.      SS.  VINCENT.      PART  SECTION  OF   SHIP  SHOWING 
MOSQUITO  PROTECTION  TO  DOORS  AND  PORTS. 

„  2.  SKETCH  SHOWING  MOSQUITO  PROTECTION  FOR 
DOORS,  VENTILATORS  AND  PORTS.  SS. 
VINCENT.      DOOR,    PORT   AND   VENTILATOR. 

„  3.  METHOD  OF  ATTACHING  WIRE-GAUZE  SCREEN 
TO   FRAMES. 

„      4.      DOORS   AND    PORTS. 

„       5.      BOAT   DECK — POOP   AND    BRIDGE   DECK. 

„     6.     MAIN  DECK To  face  page  388 

TABLE  3.     RESULTADOS  DA  CAMPANHA  ANTI-PALUDICA  NO 

XEREM To  face  page  398 

BANKS    OF    THE    ILISSOS,   ATHENS,    UNTRAINED.      BY    DR 
CARDAMATIS. 

BANKS  OF  THE   ILISSOS,  TRAINED.      BY  DR  CARDAMATIS.     To  face  page  i^^O 

FIG.    I.      F.   C.    MAILLOT. 

„       2.      PETROLAGE  D'UNE  MARE,  GITE  A  ANOPHELINES. 

„  3.  RECHERCHE  ET  PETROLAGE  DES  GITES  A 
ANOPHELINES. 

„  4.  GITE  A  ANOPHELINE  DANS  UNE  OASIS 
SAHARIENNE. 

„  5.  MAISON  PROTEGEE  PAR  DES  GRILLAGES,  CONTRE 
LES   MOUSTIQUES. 

„  6.  DEFENSE  M^CANIQUE  (PORTES  ET  FENETRES 
GRILLAGEES). 

„       7.      EXAMINATION   OF   CHILDREN. 

„       8.      SAMPLE   CHART    FOR   PUBLIC   INSTRUCTION  .     To  face  page  480 

xix 


XX  LIST   OF    ILLUSTRATIONS 

FIG.  I.  AN  EXCELLENT  TYPE  OF  MOSQUITO  -  PROOF 
HOUSE  AS  BUILT  BY  THE  TRANSVAAL 
GOVERNMENT. 

„  2.  AN  EXAMPLE  OF  ROUGH  BUT  EFFICIENT 
MOSQUITO    PROOFING   IN   THE  VELDT. 

„       3.      AN   INGENIOUS  IDEA. 

„       4.      A  GOOD  EXAMPLE  OF  MOSQUITO-PROOF   HOUSE. 

„  5.  JOINT  OFFICES  OF  THE  WITWATERSRAND 
NATIVE  LABOUR  ASSOCIATION,  AND  THE 
PORTUGUESE  DEPARTMENT  OF  EMIGRATION 
AT  RESSANE  GARCIA,  PORTUGUESE  EAST 
AFRICA. 

„  6.  ACTUAL  BREEDING  -  PLACES  OF  ANOPHELINE 
MOSQUITOS  ON  THE  CROCODILE  RIVER, 
EASTERN   TRANSVAAL. 

„       7.      COMFORT  WITH   SAFETY. 

„  8.  ACTUAL  BREEDING  -  PLACES  OF  ANOPHELINE 
MOSQUITOS   IN   THE  EASTERN   TRANSVAAL. 


To  face  page  544 


1.  PORT   LOUIS,   MAURITIUS,   BARRACKS  AND   HUTS. 

2.  THE    CAUSE    OF     THE    MALARIA    AMONGST    THE 

TROOPS   IN   THE   HUTS. 

3.  ANOPHELINE  BREEDING-GROUND  IN  A  COLONIAL 

CANTONMENT  (MAURITIUS). 

4.  PART  OF  AN   OLD   FRENCH   FORTIFICATION   AND    . 

MOAT  NEAR   PORT  LOUIS,   MAURITIUS. 

5.  COOLIES   "ROUGH  TRAINING"   A   STREAM.      THE 

SAME   FINISHED. 

6.  INDIAN   VILLAGE  IN   THE    MIDDLE  OF    A   MARSH 

(CLAIRFOND,   MAURITIUS). 

7.  A   NATIVE   HUT   IN  THE  SAME  VILLAGE. 

8.  CLAIRFOND       MARSH       IN       MAURITIUS,       WITH 

VILLAGE  NEAR  BY To  face  page  6zo 


THE   PREVENTION  OF    MALARIA 


CHAPTER  I 

HISTORY 

1.  Ancient  Times. — Dr  Richard  Caton  has  kindly  tried 
to  ascertain  for  me  whether  there  are  any  distinct  references 
to  malaria  in  the  ancient  Egyptian  writings  ;  but  informs  me 
that  he  knows  of  none  in  the  medical  papyri  or  temple 
inscriptions,  and  that  Dr  J.  H.  Walker  confirms  this  state- 
ment. It  should  be  noted  that  Strabo  (first  century  B.C.) 
observed  that  Alexandria,  in  spite  of  marshes  in  the  neighbour- 
hood, was  free  from  malaria  in  his  time ;  and  even  at  the 
present  day  the  disease  does  not  abound  in  Egypt  as  much 
as  might  be  expected. 

In  Greece  and  Italy,  however,  malaria  has  been  well  known 
for  more  than  two  thousand  years ;  and  Greek  and  Italian 
authors  have  collected  many  references  to  it  in  old  writings. 
Recently  Mr  W.  H.  S.  Jones  has  given  us  a  laborious  and 
exhaustive  study  of  the  subject  made  in  the  light  of  our 
present  knowledge  [1907,   1909]. 

The  first-named  authors  have  always  taught  that  the  disease 
was  very  prevalent  in  those  countries  from  the  first ;  but  Mr 
Jones,  following  a  tentative  suggestion  of  mine,  gives  many 
reasons  in  favour  of  the  view  that  it  may  have  entered  them 
from  without  during  historical  times,  and  may  subsequently 
have  exerted  considerable  influence  upon  their  civilisation. 
Thus,  there  are  few  references  to  it  in  the  earliest  literature, 

A 


2  HISTORY  [Sect. 

but  many  in  later  writings.  Homer  (say  iioo  B.C.)  mentions 
what  might  be  malaria,  but  only  once  {Iliad,  xxi.  31);  and 
Hesiod  (say  735  B.C.),  though  he  lived  at  Orchomenos  on  the 
shore  of  Lake  Kopais,  now  intensely  malarious,^  and  dealt 
with  rural  subjects,  makes  no  clear  reference  to  it.  Theognis 
(say  550  B.C.)  probably  mentions  it,  and  Heroditus  (494  B.C.) 
possibly  so.  Jones  infers  from  the  medical  writings  attributed 
to  Hippocrates  that  paludism  was  known  in  the  medical 
schools  before  his  birth  (about  460  B.C.) ;  and  from  the  Wasps 
of  Aristophanes  (425  B.C.)  that  it  "  was  attracting  particular 
attention  at  Athens "  at  that  time.  About  429-400  B.C.  the 
Athenians  erected  on  the  Acropolis  a  statue  to  Athena  Hygieia, 
and  introduced  the  worship  of  Asclepius,  tending  to  show  that 
"  ill  health  was  distinctly  on  the  increase " ;  and  after  this 
"references  to  fevers  became  much  more  numerous,"  and 
malaria  probably  very  common  in  Greece.  He  describes 
accurately  and  fully  the  effect  which  this  must  have  had  on 
its  civilisation. 

Apart  from  the  literature,  I  am  strongly  of  the  opinion, 
based  upon  many  considerations,  that  malaria  could  scarcely 
have  been  very  rife  in  Greece  before  the  height  of  its  prosperity. 
The  people  were  too  vigorous  and  warlike.  The  gymnastic 
training  of  youths  could  scarcely  have  been  possible  if  enlarge- 
ment of  the  spleen  had  been  very  prevalent.  The  figures  on 
the  tombstones,  though  evidently  idealised,  do  not  suggest  to 
my  own  medical  apprehension  anything  resembling  a  malarious 
race  ;  and  the  open-air  life  and  ceremonies  do  not  suggest 
a  malarious  country.  The  ancient  flourishing  population  round 
Lake  Kopais,  for  example,  would  have  been  simply  impossible 
if  the  disease  had  been  as  rife  then  as  it  is  now.  It  is 
now  very  rife  there  and  in  most  of  the  Grecian  villages ; 
and  there  must  have  been  a  time  when  the  change  took  place. 
Quite  possibly  it  was  introduced  about  the  fifth  century  before 

1  In  1906  I  found  that  twenty  out  of  forty  children  at  Orchomenos  were  suffering 
from  enlarged  spleen  in  June,  that  is  before  the  malaria  season. 


i]  ANCIENT   TIMES  3 

Christ  by  soldiers  or  slaves  from  abroad,  as  it  was  certainly 
introduced  into  Mauritius  in  1866  (section  30(21)).  Spreading 
gradually  up  the  valleys,  it  would  have  tended  to  destroy 
rural  prosperity,  to  drive  the  people  into  the  healthier  towns 
(as  in  Mauritius),  and,  assisted  by  other  causes,  to  sap  the 
vigour  and  physique  of  the  race  [Ross,  1906]. 

It  is  well  known  that  the  ancient  Greeks  recognised  the 
quartan,  tertian,  quotidian  and  semitertian  (probably  malignant 
tertian)  varieties  of  paludism,  and  many  of  its  accidents ;  and 
were  acquainted  with  its  seasonal  and  local  variability,  and, 
above  all,  with  its  frequent  prevalence  near  marshes.  This 
last  point  is  most  germane  to  our  present  part  of  the  subject. 
Thus  there  is  an  old  story  that  Empedocles  of  Agrigentum 
(say  550  B.C.)  "delivered  Selinus  (in  Sicily)  from  a  plague 
by  draining  its  marshes,  or  by  turning  two  rivers  into  them  " 
— that  he  was  able,  as  Matthew  Arnold  says,  to 

"  Cleanse  to  sweet  airs  the  breath  of  poisonous  streams." 

Doubt  has  of  course  been  thrown  on  the  story  ;  but  whether 
it  is  true  or  not  matters  little.  The  mere  fact  that  such  a 
tale  was  told  proves  that  the  Greeks,  even  at  an  early  date, 
had  become  in  some  way  aware  that  marshes  tend  to  generate 
sickness,  and,  still  more  important,  that  by  drainage  or  other 
treatment  this  may  be  prevented.  There  are  many  passages 
connecting  malaria  with  marshes.  Thus  as  already  stated 
Strabo  (first  century  B.C.)  says  that  Alexandria,  in  spite  of 
its  site,  was  free  from  marsh-fever  even  in  his  time.  "It  is 
to  be  inferred  from  this,"  Mr  Jones  says,  "  that  damp  places 
were  generally  known  to  be  unhealthy,  so  that  exceptions  to 
the  rule  were  noticed  by  observers  as  remarkable  phenomena." 
Hippocrates  (Airs,  Waters,  Places)  noticed  that  those  who  live 
in  low,  meadowy  and  hot  districts  tend  to  be  neither  tall  or 
well-built,  but  stout,  fleshy,  dark-haired,  dark-coloured,  bilious, 
and  wanting  in  courage  and  endurance. 

For   ancient  Italy  we   have  a  similar  theory,  namely,  that 


4  HISTORY  [Sect. 

references  to  paludism  are  scanty  in  the  earlier  writers,  but 
very  abundant  in  the  later  ones.  Mr  Jones  notices,  both  for 
Greece  and  Italy,  that  many  of  the  most  ancient  settlements 
appear  to  have  been  made  on  sites  which  are  now  pestilential 
— suggesting  that  they  were  not  so  unhealthy  when  they  were 
first  selected.  Professor  R.  C.  Bosanquet  tells  me  that  some 
of  the  oldest  settlements  in  Crete,  made  during  the  wonderful 
ancient  civilisation  of  that  country  thousands  of  years  before 
Christ,  were  situated  at  spots  which  are  now  intensely  malarious. 
Many  areas  round  Rome,  now  scarcely  habitable,  were  the 
homes  of  great  and  prosperous  peoples  in  the  prehistoric  period, 
and  were  later  full  of  the  country  villas  of  rich  Romans.^ 

Those  who  consider  that  malaria  was  always  very  prevalent 
in  ancient  Greece  and  Rome  cite  legends  such  as  that  of  the 
destruction  of  the  Lernean  Hydra  by  Hercules — the  Hydra 
being  supposed  to  be  symbolic  of  malaria.  Lerna  is  a  marshy 
district  in  Greece,  and  the  Hydra  was  fabled  to  inhabit  the 
marshes  and  to  ravage  the  country  round  it.  It  is  possible, 
however,  that  the  fable  refers  merely  to  the  drainage  of  the 
swamps  for  agricultural  purposes.  In  Italy  there  was  a  vast 
and  very  old  system  of  soil-drainage  by  cuniculi^  probably 
constructed  by  the  Etruscans  ;  and  some  have  suggested  that 
this  drainage  was  carried  out  against  malaria,  and  that  it 
enabled  the  ancients  to  build  villas  at  spots  now  deadly. 
Here,  again,  the  object  of  the  drainage  was  more  probably 
agricultural.  I  should  like  to  believe  that  it  was  a  sanitary 
drainage,  but  find  difficulty  in  doing  so.  Drainage  against 
malaria  must  obviously  be  an  urban  and  not  a  rural  measure. 
The  cost  of  draining  all  the  country  round  Rome  merely  for 
sanitary  purposes  would  have  depleted  the  sanitary  budget 
even  of  the  logical  ancients.  Mr  Jones's  view  appears  the  more 
probable  —  namely  that  the  disease  was  possibly  introduced 
at  the  time  of  the  first  foreign  expansions,  both  in  Greece  and 
Italy,  and  that  it  gradually  became  intensified  owing  to  the 
^  See  also  F.  Genovese  [1909]. 


i]  ANCIENT  TIMES  5 

causes  described  in  sections  30  (20).  North  [1896]  ascribes  the 
intensification  to  rural  depopulation — due  to  wars  or  to 
economical  changes.  I  think  it  more  probable  that  the  malaria 
produced,  or  helped  to  produce,  the  rural  depopulation ;  and 
we  now  have  the  living  picture  of  the  process  before  our  eyes 
in  Mauritius.  Possibly  also  the  disease  has  always  had  a 
tendency  to  eliminate  or  repel  the  fair  strain  of  blood  from 
the  north,  leaving  the  darker  southern  strains  predominant. 
But  the  effect  in  Italy  was  probably  less  than  in  Greece, 
owing  to  the  much  smaller  proportion  of  malarious  area  in 
the  former. 

Of  course  the  Roman  writers,  both  medical  and  non-medical, 
were  acquainted  with  the  leading  facts  about  paludism 
mentioned  above.  The  erudite  Varro  (116-28  B.C.)  says  in 
his  Renan  Riisticamm,  "  Animadvertendum  etiam  si  quo  erunt 
loca  palustria,  et  propter  easdem  causas,  et  quod  crescunt 
animalia  quaedam  minuta,  quae  non  possunt  oculi  consequi, 
et  per  aera  intus  in  corpus,  per  os  ac  nares  perveniunt  atque 
difficiles  efficiunt  morbos" — that  in  marshes  there  are  animals 
too  small  to  be  seen,  but  which  enter  the  mouth  and  nostrils 
and  cause  troublesome  diseases.  Other  famous  passages  are 
from  Columella  (about  the  first  century  B.C.),  who  says  that 
bogs  breed  insects  armed  with  stings,  and  pestilent  swimming 
and  creeping  things,  from  which  come  obscure  diseases.  Here 
we  have  malaria  connected  not  only  with  the  marsh,  but 
with  insects  or  germs  bred  in  the  marsh.  Cicero  and  Seneca 
say  that  paludism  depopulated  certain  districts.  Mr  Robert 
Gladstone  and  Mr  Jones  have  kindly  called  my  attention  to 
several  passages  referring  to  mosquito  nets,  called  conopeuni  by 
the  Romans,  after  the  Greeks  (our  word  canopy).  Herodotus 
first  noted  with  surprise  the  use  of  them  in  Egypt  ;  and  they 
are  referred  to  later  in  Varro  {^De  Re  Riistica  2,  10,  8),  Horace 
{Epodes,  9,  16),  Propertius  (3,  11,  45),  Juvenal  (6,  80),  and 
Paulus  Silentiarius  {A7tihologia  Palatind).  Horace  says,  "And 
among  the   military   standards,   oh,   shame !    the    sun    sees   a 


6  HISTORY  [Sect. 

mosquito  curtain  ; "  and  Propertius  calls  these  nets  foeda  (foul 
or  disgraceful).  Evidently  the  ancients  felt  towards  them  as 
do  many  of  our  own  more  manly  colonists  who  prefer  annoy- 
ance and  even  sickness  to  disgrace  !  But  Paulus  Silentiarius 
thought  that  they  were  useful  for  a  post-prandial  siesta  in  order 
to  save  the  slaves  the  trouble  of  using  a  fly-flapper.  Varro 
said  that  women,  lately  confined,  spent  a  number  of  days  in 
them ;  and  Juvenal  said  that  they  were  used  to  cover  the 
cradles  of  the  rich  and  noble. 

On  the  6th  February  1905,  Sir  Henry  Blake,  Governor 
of  Ceylon,  called  the  attention  of  the  Ceylon  Branch  of  the 
Royal  Asiatic  Society  to  the  fact  that  certain  ancient  Sinhalese 
writers,  who  lived  certainly  more  than  1400  years  ago,  had 
connected  fever  with  mosquitos.  The  original  authority 
appears  to  be  Susruta,  in  the  chapter  on  Insects  which  forms 
the  last  chapter  of  his  book  on  Poisons.  He  says  that  there 
are  five  kinds  of  mosquitos,  one  of  which  "  produces  the  same 
symptoms  as  deadly  insects."  J.  Jolly,  however,  discussed  the 
subject  [1905],  and  thinks  that  Susruta  was  merely  referring 
to  the  irritation  caused  by  the  bites.  He  attributed  malaria, 
J.  Jolly  says,  to  derangement  of  the  humours.  Personally,  so 
far  as  I  can  judge,  I  doubt  whether  these  writers  ever  really 
connected  malaria,  even  in  imagination,  with  the  insects.^ 

2,  Early  Modern  Times. — Little  was  added  to  our  know- 
ledge during  the  next  thousand  years ;  but  about  1640  the 
inestimable  boon  of  Cinchona  bark  was  introduced  into  Europe. 
The  Countess  d'El  Cinchon,  wife  of  the  Viceroy  of  Peru,  had 
been  cured  of  fever  by  means  of  it  in  that  country,  where 
it  had  been  discovered  by  the  Indians  near  Loxa  (?)  ;  and  she 
was  wise  enough  to  send  it  home  to  Europe.  The  use  of  it, 
after   many   checks,  gradually   spread  ;    and   in    1820  Pelletier 

^  I  can  ascertain  little  about  malaria  in  early  days  in  America ;  but  according  to  a 
suggestive  paper  by  O.  Effertz,  the  disease  was  probably  introduced  there  from 
Europe,  just  as  the  converse  happened  with  syphilis  [1909]. 


2]  EARLY   MODERN   TIMES  7 

and  Caventou  extracted  the  alkaloid  quinine  from  it.  But 
the  discovery  of  this  specific  has  not  only  proved  to  be  a 
blessing  for  the  treatment  of  untold  millions  of  human  beings, 
but  also  enabled  Morton  [1697]  and  Torti  [1753]  to  separate 
the  malarial  fevers,  which  are  cured  by  it,  from  those  upon 
which  it  has  no  influence,  and  by  this  means  to  differentiate 
and  study  the  symptoms  of  the  former.  Morton  also  recalled 
the  old  hypothesis  of  the  marsh  ;  and  this  was  amplified  by 
Lancisi,  who  repeated  the  views  of  Varro  and  Columella  in 
greater  detail  in  his  book  De  noxiis  paluduni  effluviis.  He 
stated  that  fevers  disappear  after  drainage,  and  attributed 
the  poison  either  to  inorganic  or  organic  emanations  from  the 
marsh.  He  studied  mosquitos,  and  even  suggested  inoculation 
by  them  as  a  possible  means  of  infection — though  he  also 
thought  that  their  larvae  foul  drinking  water  [17 17]. 

It  is  now  apparent  that  the  world  had  been  gradually 
becoming  aware  during  centuries  of  the  paludic  nature  of 
malarial  fever,  not  by  direct  experiment  or  even  by  investiga- 
tion, but  by  a  kind  of  subconscious  experience  based  on  public 
observations.  In  Italy  especially,  where  of  all  civilised  countries 
the  disease  was  most  prevalent,  this  process  was  most  apparent 
— so  much  so  that,  as  North  describes  [1896],  the  peasantry 
can  often  tell  at  sight  which  localities  are  likely  to  be 
"  malarious."  More  than  this,  by  similar  general  observation, 
the  good  effect  of  assainment  of  marshes  had  become  equally 
notorious  there.  Thus,  as  early  as  1667,  Doni  wrote  a  work 
called  De  Restituenda  Sahibj'itate  Agri  Romani ;  and  references 
to  a  succession  of  works  carried  out  on  this  principle,  which 
I  now  call  the  principle  of  Mosquito  Reduction,  are  given  by 
Celli  [1901].  At  the  same  time  efforts  were  made  by  many 
observers,  such  as  Morton,  Lancisi,  Lind,  Pringle,  to  explain 
the  paludic  connection  ;  and  these  resulted  in  the  formation 
of  the  hypothesis  of  the  pahidic  miasma.  This  was  supposed 
to  be  some  kind  of  infecting  emanation  from  stagnant  water, 
either   chemical,  or  as   Lancisi  suggested,  organic ;   but  in  no 


8  HISTORY  [Sect. 

cases,  apparently,  were  experiments  made  to  test  the  point. 
Later,  when  it  was  observed  that  malaria  may  sometimes  occur 
where  there  is  no  marsh,  the  hypothesis  of  the  paludic  miasma 
was  extended  to  that  of  the  telluric  miasma,  according  to  which 
the  poison  exists  not  only  in  marshes  but  anywhere  in  suitable 
soil,  from  which  it  rises  at  night  or  when  the  soil  is  disturbed. 
This  speculation,  for  it  is  nothing  more,  is  not  quite  dead  even 
yet,  though  the  observation  which  originated  it  is  easily  ex- 
plained otherwise.  The  word  "  malaria  "  {maV  aria  or  bad  air) 
is  derived  from  it. 

3.  Discovery  of  the  Parasites.  —  Last  century,  however, 
pathological  science  was  no  longer  content  with  mere  guesses 
at  the  truth,  but  began  to  demand  strict  microscopical  and 
experimental  evidence.  Applied  to  paludism,  this  method  gave 
an  early  reward.  In  1847,  H.  Meckel  discovered  innumerable 
black  granules  in  the  blood  of  an  insane  patient ;  and  the 
discovery  was  subsequently  confirmed  and  amplified  by  Dlauhy, 
Virchow,  Heschl,  Planer  and  Arnstein — the  granules  now  being 
known  under  the  name  of  the  paludic  pigmejit,  or  melanin,  or 
haematozoin  (Sambon).^  For  a  long  time  they  were  thought 
to  be  due  to  a  chemical  action  of  the  paludic  miasma  on  the 
red  cells  of  the  blood. 

About  the  same  time  many  laborious  attempts  were  made 
to  discover  some  animal  or  vegetable  organism  which  lives  in 
marshes  and  produces  paludism.  As  long  ago  as  1846  Rasori 
(cited  by  S.  Calandruccio)  made  an  extraordinary  prediction  on 
this  subject.  "  For  many  years,"  he  said,  "  I  have  held  the 
opinion  that  the  intermittent  fevers  are  produced  by  parasites 
that  cause  the  successive  paroxysms  of  fever  by  their  repro- 
duction, which  occurs  periodically  more  or  less  rapidly  according 
to  their  species " — and  this  has  proved  to  be  exactly  true. 
Many  writers  attributed  the  disease  to  various  marsh-growing 
vegetables.     In  1862  Salisbury  in  particular,  after  considerable 

^  I  suggest  the  name  Plasmodin,  which  is  still  more  exact. 


3]  DISCOVERY   OF  THE   PARASITES  9 

study,  blamed  a  kind  of  Pabnella;  and  after  1878,  a  number 
of  Italian  workers,  Lanzi  and  Terrigi,  Edwin  Klebs  and  C. 
Tommasi-Crudeli,  thought  that  they  had  actually  incriminated 
certain  fungi  or  bacteria,  which  they  said  swarm  in  malarious 
places,  occur  in  the  blood,  produce  spores  before  each  paroxysm 
of  fever,  and  cause  similar  infection  in  animals.  These  findings 
were  even  confirmed  by  Marchiafava  and  other  Italians ;  but 
have  now  been  completely  discredited. 

In  1878,  however,  A.  Laveran  commenced  his  studies  of  the 
subject  at  Bone  in  Algeria,  by  following  up  the  granules  of 
pigment,  already  referred  to,  in  the  blood  of  living  patients. 
He  was  struck  by  the  fact  that  they  were  frequently  contained 
within  cells  possessing  active  amoeboid  movements  ;  and,  finally, 
on  the  6th  November  1880,  at  Constantine,  he  detected  the 
microgametes  issuing  from  the  male  cell.  Though  at  the  time 
he  did  not  know  the  nature  of  this  phenomenon,  it  convinced 
him  that  he  was  dealing  with  a  living  parasite  of  the  human 
red  corpuscles.  In  fact  the  black  granules  are  merely  the 
excrementitious  matter  produced  by  the  parasites  from  the 
substance  of  the  red  cells,  and  contained  within  their  bodies, 
or  released  in  the  tissues  of  the  host.^ 

About  the  same  time  C.  Gerhardt  proved  that  healthy 
persons  can  be  infected  by  the  inoculation  of  blood  of  patients 
suffering  from  paludism  [1884].  His  experiments  were  after- 
wards verified  by  many  workers,  and  demonstrate  (apart  from 
the  microscopical  discovery  of  the  parasites)  that  the  disease 
is  not  due  to  any  gaseous  emanation  from  marshes,  but  is  a 
true  infection  by  some  living  virus. 

In  1886  and  subsequently,  C.  Golgi,  who  v/as  favourably 
situated  in  Pavia  for  the  work,  showed  clearly  that  the  parasites 

1  Recently  R.  Blanchard  (Archi.  de  Parasitologic,  vol.  vii.  1903)  would  have  us 
believe  that  one  P.  F.  H.  Klencke  had  discovered  the  parasite  of  malaria  before 
Laveran  ;  but  it  is  perfectly  obvious  from  Klencke's  drawings,  given  by  Blanchard, 
that  his  "parasites"  are  merely  the  usual  artifacts  found  in  fresh  blood.  Klencke, 
moreover,  was  not  studying  malaria  at  all,  but  "vertigo."  Medical  literature  is  full  of 
such  simulacra. 


lo  HISTORY  [Sect. 

reproduce  by  simultaneous  sporulation  ;  that  the  febrile  paroxysm 
in  the  patient  commences  at  the  moment  when  these  spores  are 
liberated  (just  as  Rasori  had  divined) ;  and  that  the  parasites 
of  quartan  and  mild  tertian  fever  are  morphologically  different 
[1886].  A  little  later,  Canalis,  and  Marchiafava  and  Celli  dis- 
covered similar  facts  regarding  the  malignant  parasites,  and 
showed  that  they  differ  from  the  quartan  and  mild  tertian 
parasites  ;  and  Marchiafava  and  Bignami  suggested  that  they 
are  of  two  varieties,  the  malignant  tertian  and  the  quotidian. 
In  1885  Danilewsky  discovered  similar  parasites  in  birds  and 
several  other  animals ;  and  subsequently  Marchiafava,  Celli, 
Bignami,  Mannaberg  and  others,  made  many  careful  studies  of 
the  parasites,  and  of  their  effects  in  human  beings  ;  Romanowsky 
found  the  proper  way  to  stain  them ;  and  many  observers 
verified  these  researches  in  various  parts  of  the  world — the 
literature  amounting  to  some  hundreds  of  publications, 

4.  Speculations  regfardin^  the  Mode  of  Infection.— But  the 

question  now  arose — an  all-important  question  in  connection 
with  the  prevention  of  the  disease — How  do  these  parasites 
manage  to  effect  an  entry  into  the  blood  of  men  and  animals  ? 
Most  observers,  remembering  that  the  disease  often  abounds  in 
the  neighbourhood  of  marshes,  assumed  at  once  that  Laveran's 
parasites  must  be  capable  of  living  in  a  changed  form  in  stagnant 
water ;  and  some  actually  sought  them  there.  Thus  Grassi  and 
Calandruccio  suggested  that  a  free  living  amoeba  is  really  the 
external  stage  of  the  organism.  On  the  other  hand,  experiments 
to  infect  healthy  persons  by  water  from  marshes,  made  by 
Marchiafava  and  Celli  [1885],  Marino  [1890],  and  especially 
Agenore  Zeri  [1890]  failed  entirely.  Zeri  gave  marsh  water 
to  nine  persons  to  drink  in  doses  from  r5  to  3  litres  a  day  for  a 
number  of  days.  To  another  five  persons  he  gave  the  water 
by  clyster  ;  and  to  sixteen  by  spray  inhalation — yet  no  paludism 
followed.  Like  all  negative  results,  his  are  not  absolutely  con- 
clusive— since  the  failure  may  have  been  due  to  some  unforeseen 


4]  DISCOVERY   OF   METAXENY  ii 

condition  absent  from  the  experiments  ;   but  his  paper  is  too 
important  to  have  been  forgotten  as  much  as  it  has  been. 

Before  describing  my  own  Indian  researches  which  com- 
menced at  this  point,  it  is  necessary  to  survey  our  general 
parasitological  knowledge,  together  with  the  state  of  thought 
regarding  malaria,  at  the  time.  Discoveries  concerning 
Laveran's  bodies,  which  are  animal  and  not  vegetable  organisms, 
have  a  line  of  descent  from  previous  discoveries  concerning 
animal  parasitology,  and  not  directly  from  bacteriology. 

Many  of  the  large  animal  parasites  of  man  and  animals  have 
been  known  to  us  from  antiquity,  but  until  the  beginning  of 
the  eighteenth  century,  were  supposed,  like  other  low  forms  of 
life,  to  be  created  in  each  host  by  "  spontaneous  generation." 
Even  long  after  Redi  (1668)  proved  that  this  hypothesis  did 
not  hold  for  certain  insects,  it  was  still  supposed  to  apply  to  the 
parasites.  Gradually,  however,  large  numbers  of  the  latter  were 
discovered,  and  Pallas  put  forward  the  view  that  they  originate, 
like  other  animals,  from  eggs,  which  escape  from  an  infected 
person  or  animals,  and  are  by  chance  swallowed  by  another 
host.  Such  a  history  is,  in  fact,  quite  correct  for  many  parasites ; 
but  in  1790  Abildgaard  made  the  remarkable  discovery,  by 
experiment,  that  the  parasites,  called  Bothriocephalus  solidus 
and  Ligula,  inhabit  for  a  part  of  their  lives  certain  fish,  and 
reach  maturity  only  in  certain  water-fowl  which  happen  to 
swallow  the  infected  fish.  This  appears  to  have  been  the  first 
found  instance  of  the  wonderful  process  of  metaxeny,^  or  change 
of  host.  The  idea  was  lost  sight  of  for  years  until  Eschricht  in 
1 84 1,  and  Steenstrup  in  his  famous  work  on  the  alternation  of 
generations  of  Trematodes  (1842),  recalled  it.  It  was  finally 
established  for  Cestodes  by  F.  Kiichenmeister,  physician  to  the 
Duke  of  Saxe  Meiningen,  in  1851-1853,  by  means  of  direct 
experimental  feeding  methods  first  used  by  him.     Metaxenous 

^  I  use  this  word  on  the  authority  of  De  Bary,  who  employs  the  incorrect  form 
metoxenous  in  the  above  sense — see  his  book  on  Fungi,  Mycetozoa,  and  Bacteria. 
Trans.  Clarendon  Press,  Oxford,  1887,  p.  387. 


12  HISTORY  [Sect. 

parasites  are  those  which  spend  part  of  their  life  in  one  kind 
of  animal,  and  the  rest  of  it  in  another — generally  the  early 
part  of  their  existence  in  one  host,  and  the  mature  sexual  part 
of  it  in  another  host  which  preys  upon  the  first  one,  as  in  the 
rabbit  and  the  dog,  the  mouse  and  the  cat,  swine  and  men,  and 
so  on.  Moreover,  he  proved  that  the  eggs  or  young  of  the 
mature  parasites  are  able  to  pass  back  again  into  individuals 
of  the  first  species  of  host,  from  which  they  are  again  trans- 
ferred to  the  second  species  of  host — and  so  on,  ad  infinitum. 
This  great  discovery,  which  may  almost  be  called  the  basis 
of  modern  parasitology,  was  rapidly  verified  by  Kiichenmeister 
and  Leukart  for  many  parasites.  At  first  it  was  applied  to 
those  of  the  higher  animals;  but  before  1858  Leukart  dis- 
covered that  the  Nematode  worm,  Cucullanus  elegans  of  the 
perch  develops  in  the  little  aquatic  Arthropod  called  Cyclops, 
or  the  Water  Flea.  Next,  perceiving  the  resemblance  of  this 
worm  to  the  famous  Filaria  medinensis,  or  Guinea  Worm  of 
man,  he  suggested  in  the  same  year  (1858)  to  the  young 
Russian  naturalist  and  traveller,  Fedschenko,  that  the  latter 
parasite  may  also  pass  a  stage  of  its  life  in  a  Cyclops.  The 
Guinea  Worm  lives  under  the  human  skin,  and  emits  its  young 
through  an  ulcer  which  it  produces  in  the  integument — the 
young  next  finding  their  way  into  water.  A  few  months  later 
Fedschenko  proved  by  experiments  in  Turkestan  that  Leukart 
was  right.  He  watched  the  development  of  the  embryos  in  the 
Cyclops ;  but  did  not  complete  the  cycle  by  infecting  men  from 
the  latter.  He  supposed,  however,  that  men  become  infected 
by  accidentally  swallowing  infected   Cyclops  in  drinking  water.^ 

^  For  an  account  of  this  discovery  see  R.  Leukart,  Die  Menschlichen  Parasiten, 
1876,  vol.  ii.  p.  704.  As  it  is  an  extremely  important  discovery,  I  have  been  at 
considerable  pains  to  ascertain  the  exact  dates.  It  will  scarcely  be  believed,  but 
Leukart's  complete  works  are  difficult  to  obtain  in  this  country.  I  am  indebted  to 
Dr  R.  T.  Leiper  for  having  studied  the  question.  The  facts  appear  to  be  as  follows  : 
In  1858  Leukart  (when  at  Naples)  suggested  the  idea  to  Fedschenko,  who  was  then 
about  to  proceed  to  the  East ;  but  did  so  as  a  secret  (?).  In  1865  and  1866  Leukart 
first  published  his  account  of  the  development  of  Cttcullanus  in  Cyclops,  but  merely 
hints  at  the  idea  that  F.  medtnensis  has  a  similar  development,  without  mentioning 
Cyclops  as  the  possible  second  host.     In  1869  Fedschenko  seems  to  have  returned  from 


4]  TRANSMISSION    OF    FILARIAE  13 

In  1868  another  important  case  was  discovered  by  Leukart 
and  Melnikoff  in  Leukart's  laboratory.  They  found  that  the 
yowngoi Dipylidimn  caniniuvi  {Taenia  cucumerina),  sl  parasite  of 
dogs  and  cats,  develops  in  the  dog-louse  ^ — this  being,  I  believe, 
the  first  case  in  which  a  parasite  of  a  mammal  was  found  to 
be  transferable  by  any  kind  of  vermin  which  feeds  on  that 
mammal.  The  great  credit  due  to  Leukart  in  connection  with 
these  discoveries  has  been  much  overlooked  of  late. 

Filaria  bancrofti^  a  human  parasite,  was  discovered  in  the 
adult  form  by  Bancroft  in   1876,  though  its  embryos  had  been 
found  by  Demarquay  in   1863  in  chylous  fluid,  and  by  Lewis 
in  blood  in   1872.     In  the  Lancet,  12th  January  1878,  Cobbold 
mentions  a  suggestion  of  Bancroft,  dated  the  20th  April   1877, 
that  the  worm  (which  is    closely  allied   to  F.  medinenszs,  and 
indeed    to    Cucullanus)    might    be    carried    by   mosquitos.     In 
1877,  P.  Manson,  in  Amoy,  China,  came  to  the  same  conclusion, 
and  on  examining  a  number  of  mosquitos  fed  on  a  Chinaman 
whose   blood    contained   the    embryos,   discovered    that   these 
develop   in  the  tissues  of  the   insects  just  as  the  embryos  of 
F.  medinensis  develop  in  Cyclops?     This  was  the  first  time  that 
metaxeny  was  found  to  occur  with  any  parasite  between  man 
and  mosquitos ;  but  Manson  did  not  observe  the  development 
of  the   embryos   to   a   stage    much  more   advanced   than  that 
observed  by  Fedschenko  in  the  Cyclops.     He  thought  also  that 
mosquitos  die  on  the  surface  of  water  a  few  days  after  feeding 
on    blood ;    and    that   the   partially   developed    embryos   then 
liberate  themselves  from  the  dead  insects,  and,  after  swimming 
free   in    the  water,  are   swallowed  by  human  beings.     But  he 
did  not  prove  this;  and  indeed,  in  1900,  G.  C.  Low  and  S.  P. 
James,   acting   on    the    evident    suggestions   of  my    work    on 

Turkestan  and  to  have  published  his  paper  in  Russian,  describing  the  development  of 
F.  medinensis  in  Cyclops.  The  last,  then,  must  be  taken  as  the  date  of  publication  of 
the  discovery.    Dr  A.  Jacobi,  Leukart's  biographer,  can  give  me  no  further  information. 

^  R.  Leukart,  Die  Menschlichen  Parasilen,  1876,  vol,  ii.  p.  704. 

"  P.  Manson,  Filaria  sanguinis  hominis  a7id  Certain  New  Forms  of  Parasitic 
Diseases.    London,  1883. 


14  HISTORY  [Sect. 

malaria,  made  observations  which  lead  us  to  think  that  the 
embryos  return  to  human  beings  through  the  insect's  proboscis. 
By  his  detailed  studies,  however,  Manson  has  built  up  most  of 
our  present  knowledge  on  the  subject  of  filarial  disease  in  man. 

It  should  be  noted  here  that  all  these  examples  of  metaxeny 
apply  only  to  the  higher  parasites,  the  Helminths  or  Worms, 
and  that  in  some  of  the  cases,  including  those  of  Fedschenko 
and  Manson,  the  life-cycle  had  been  by  no  means  completely 
ascertained  —  so  much  so  that  many  doubted  whether  the 
observed  development  of  the  embryos  in  Cyclops  and  Culex 
could  be  looked  upon  as  a  genuine  stage  of  metaxeny.  But 
the  bodies  discovered  by  Laveran  belong  to  a  much  lower,  in 
fact  to  the  lowest,  class  of  animals — the  Unicellular  ones. 
Though  many  organisms  of  this  class — amoebas,  gregarines, 
coccids,  trypanosomes — have  been  discovered  in  various  animals, 
yet  up  to  1889  not  one  of  them  had  been  proved  to  be 
metaxenous.  During  this  year,  however,  a  remarkable  dis- 
covery was  made  by  Theobald  Smith  and  F.  L.  Kilborne  in 
America  in  connection  with  the  disease  called  Texas  cattle- 
fever.  For  a  long  time  the  farmers  had  thought  that  it  is 
caused  by  certain  cattle-ticks.  Smith  and  Kilborne  now  showed 
that  the  disease  is  due  to  minute  parasites  of  the  red  corpuscles, 
akin  to  the  parasites  of  malaria  but  not  belonging  to  the  same 
group,  called  Piroplasma  bigeminuni ;  and  that  they  are 
inoculated  in  some  way  into  healthy  cattle  by  the  bites  of 
young  ticks  born  from  a  parent  tick  which  has  fed  upon  a 
diseased  ox.  This  fact  was  conclusively  proved  by  direct 
experiment,  and  suggested  that  these  Piroplasmae,  which  are 
unicellular  animals,  might  also  be  metaxenous  like  so  many  of 
the  higher  parasites.  But  the  observers  failed  in  following  out 
microscopically  the  life-history  of  the  Piroplasma  in  the  ticks, 
and  therefore  did  not  actually  prove  any  alternate  generation 
in  them.i 

^  T.  Smith  and  F.  L.  Kilborne,  Investigations  into  the  Nature,  Causation  and 
Prevention  of  Texas  or  Southern  Cattle  Fever.  Government  Printing  Office. 
Washington,  1893. 


4]  VARIOUS    HYPOTHESES  15 

Meantime,  however,  there  had  been  many  vague  conjectures 
to  the  effect  that  several  diseases  may  be  produced  by  biting 
vermin.  Thus,  as  just  mentioned,  American  farmers  had  long 
thought  that  Texas  cattle-fever  is  carried  by  cattle-ticks.  Many 
travellers  also  related  that  African  natives  ascribed  a  peculiar 
sickness  to  the  bites  of  another  kind  of  tick  ;  and  others  said 
that  the  deadly  nagana  of  cattle  in  parts  of  Africa  is  probably 
due  to  the  bites  of  the  tsetse  fly.  And  similar  speculations 
connecting  both  yellow  fever  and  malaria  with  mosquitos  had 
long  been  rife.  Generally  derided  at  the  time,  these  views  were 
speedily  forgotten  ;  and  it  is  only  of  late  that  many  of  them 
have  been  resuscitated  and  discussed  as  instructive  relics  of 
the  past.  It  will,  I  think,  interest  the  reader  to  follow  the 
gradual  development  of  our  knowledge  of  this  important  subject. 

I  have  already  mentioned  the  curious  utterances  of  Varro, 
Columella,  the  ancient  Sinhalese  books,  and  of  Lancisi,  regard- 
ing insects  and  fever.  Nuttall  [1899,  p.  75]  gives  statements 
by  Lustig,  Rubner,  Koch  and  myself,  to  the  effect  that  the 
peasantry  in  Italy,  Tyrol,  East  Africa,  and  Assam  seemed  to 
have  vague  ideas  of  the  same  kind.  Dr  R.  H.  Kennan  informs 
me  that  he  has  found  an  old  ordinance  of  Freetown,  Sierra 
Leone,  dated  1812,  in  which  the  inhabitants  (mostly  freed 
slaves)  are  enjoined  to  keep  the  road  in  front  of  their  plots  in 
good  condition  in  order  to  prevent  the  formation  of "  stagnant 
pools  which  generate  disease  and  mosquitos  over  the  town." 
In  18^,  Dr  Josiah  Nott,  of  Mobile,  Alabama,  appears  to  have 
stated  that  both  yellow  fever  and  malaria  may  be  transmitted 
by  mosquitos,  and  refers  to  the  speculation  as  having  been 
already  advanced  as  regards  malaria.  In  1854,  however,  Louis- 
Daniel  Beauperthuy^  a  French  medical  man,  born  in  Guadeloupe 
in  1808,  gave  the  hypothesis  in  greater  detail  [1854].  As  a 
"  travelling  naturalist "  for  the  Paris  Museum  in  Venezuela,  he 
studied  both  these  diseases  microscopically,  and  concluded  that 
they  are  produced  by  a  venomous  fluid  injected  under  the  skin 
by  mosquitos,  like  the  poison  injected  by  snakes.     Marshes,  he 


i6  HISTORY  [Sect. 

says,  are  dangerous  because  of  the  mosquitos  bred  in  them,  not 
because  of  their  effluvia.  He  stated  that  several  species  of 
mosquito  carry  yellow  fever,  but  mentioned  especially  "the 
sancudo  bobo  with  legs  striped  with  white "  —  probably  the 
Stegomyta  calopus}  which  we  now  know  is  really  the  agent.  But 
he  mentions  no  experiments  in  support  of  his  opinions,  which 
seem  to  be  only  ingenious  speculations  based  upon  general 
thought  and  observation. 

In  1 88 1,  and  subsequently,  Charles  Finlay  of  Havana 
repeated  a  similar  hypothesis,  apparently  independently  of 
Nott  and  Beauperthuy  [1881].  His  views,  however,  differ  in 
an  important  particular.  While  Beauperthuy  seemed  to  think 
that  mosquitos  originally  obtain  the  disease-giving  poison  from 
the  marsh  in  which  they  breed  (and  Varro,  Columella,  and 
Lancisi  believed  the  same),  Finlay  held  (regarding  yellow  fever) 
that  they  obtain  it  from  sick  people.  In  other  words,  he 
thought  that  the  insects  simply  convey  it  from  patients  to 
healthy  persons.  The  proboscis  of  a  mosquito  which  bites  a 
patient  becomes  contaminated  by  germs  in  his  blood ;  the 
germs  multiply  in  the  proboscis ;  and  then  enter  the  blood  of 
any  person  whom  the  mosquito  bites  next — ^just  as  bacteria  may 
be  carried  on  a  soiled  surgical  instrument  from  one  person  to 
another.  He  thought  that  an  insect  which  had  only  just  bitten 
a  patient  could  convey  the  virus ;  but  that  the  longer  it  lived 
after  biting  the  patient  the  more  the  germs  would  multiply  in 
its  proboscis,  and  the  larger  the  dose  given  to  the  healthy  person 
would  be.  He  also  considered  that  the  mosquito  with  striped 
legs  {Stegomyta  calopus)  is  the  agent  of  yellow  fever.  He  records 
some  experiments  ;  but  they  must  have  been  very  doubtful,  since 
we  now  know  that  mosquitos  which  have  bitten  a  patient  must 
live  for  no  less  than  twelve  days  before  they  can  infect  a  healthy 
person.  Like  Beauperthuy,  he  rightly  conjectured  the  species 
of  mosquito  which  carries  yellow  fever,  and  actually  placed  them 
in  the  hands  of  the  men  who  ultimately  solved  the  problem. 

^  J.  Guiteras  says  not  (Lancet  l8th  June  1910). 


4]  VARIOUS   HYPOTHESES  17 

He  was  acquainted  with  Manson's  researches  on  the  develop- 
ment of  Filaria  bancrofti  in  mosquitos.^ 

In  1883  Dr  A.  F.  A.  King  wrote  an  able  paper  on  the 
subject  [1883]  in  which  he  gives  no  less  than  nineteen  reasons 
why  mosquitos  are  likely  to  carry  paludism.  These  are: — (i) 
that  both  paludism  and  mosquitos  are  connected  with  marshes; 

(2)  that  they  both  require  a  temperature  of  over  60  degrees  F. ; 

(3)  are  checked  at  freezing  point ;  (4)  abound  most  near  the 
equator  and  sea-coasts ;  (5)  have  an  affinity  for  dense  foliage ; 
(6)  can  be  screened  off  by  trees ;  (7)  can  be  transported  by 
winds  ;  (8)  are  encouraged  by  turning  the  soil  ;  (9)  are  affected 
by  "bodies  of  water";  (10)  are  diminished  by  cultivation  and 
settlement;  (11)  keep  near  the  surface  of  the  ground;  (12) 
abound  most  after  sundown;  (13)  and  in  the  open;  (14)  are 
destroyed  by  fires  ;  (15)  are  not  so  common  in  cities  ;  (16)  are 
most  prevalent  in  autumn  ;  (17)  are  arrested  by  mosquito  nets  ; 
(18)  affect  infants  (which  are  generally  protected  by  nets)  less 
than  adults ;  and  (19)  attack  whites  more  than  other  races. 
This  was  by  far  the  best  exposition  yet  given.  Though 
arguments  (4),  (13),  (14),  (18),  and  (19)  are  not  sound,  while 
arguments  (5),  (6),  (7)  are  very  doubtful,  and  though  the  most 
cogent  argument  of  all  was  not  known  to  him,  the  cumulate 
effect  of  his  careful  and  well-arranged  reasoning  was  very  strong. 
Like  Beauperthuy,  he  held  that  the  insects  bring  the  poison  from 
the  marsh  and  inoculate  it  by  their  bites.  He  was  acquainted 
with  Manson's  work,  but  not  with  Laveran's.  His  paper  was 
speedily  lost  sight  of,  and  was  not  resuscitated  until  my 
researches  had  cleared  up  the  question. 

About  the  same  time  Laveran  suggested  the  same  idea 
[1884,  p.  457]  in  a  short  sentence:  "Do  mosquitos  play  the 
same  role  in  paludism  as  infilariasis ? "  he  said.  "The  thing 
is  not  impossible,  and  we  must  note  that  mosquitos  abound 
in  all  marshy  places." 

^  For  further  details  see  the  interesting  book,  Mosquito  or  Man,  by  my  colleague, 
Sir  Rubert  Boyce.     John  Murray,  London,  1909. 

B 


i8  HISTORY  [Sect. 

Also  about  the  same  time,  during  his  famous  studies  on 
cholera  in  India,  R.  Koch  had  the  same  notion  ;  but  he 
mentioned  it  only  in  his  lectures  to  students  [Nuttall,  1899, 
p.  jy,  and  Ross  1905,  p.  73]. 

Ten  years  later,  and  some  years  after  I  had   commenced 

my  studies  of  the  subject,  P.  Manson  supported  the  mosquito 

hypothesis  in  a  rather  short  paper  [1894].     But  he  added  a 

new  and  a  stronger  argument  to  those  already  given.     In  the 

blood  of  man  the  parasites  of  malaria  consist  chiefly  of  forms 

which  reproduce  themselves  indefinitely  by  spore  formation  ; 

but  in  addition  to  these  there  are  other  forms  which  appear 

to  possess  no  function  in  the  human  body,  but  which,  shortly 

after  the  blood   containing  them  is  drawn  from   the  patient's 

finger,  often    emit    long   and    actively  motile    filaments  which 

may   break    away    from    the    parent    cell,    and   wriggle   about 

rapidly  in  the  fluid   under  the  microscope.     For  a  long  time 

these    bodies    had    been    the    subjects    of    discussion.      Some 

observers,  chiefly  of  the  Italian  school,  held  that  they  represent 

only   the   dying   struggles   of  the   parasite ;   others,    including 

Laveran  and  Danilewsky,  thought  that  they  are  really  living 

bodies ;    and    Mannaberg   even    suggested    that    they   may   be 

connected  with   the   life -history  of  the    parasites   outside  the 

human  body — though  he  did  not  explain  how  this  could   be. 

Manson  now  offered  an  explanation.     He  thought  that  when 

a  mosquito  sucks  the  blood,  these  parasites  enter  its  stomach 

with  the  blood,  and  there,  in  a  few  minutes,  emit  their  motile 

filaments  just  as  they  do  under  the  microscope.     The  motile 

filaments,    he    thought,    were    flagellated    spores,    which    next 

pass  through  the  walls  of  the  mosquito's   stomach  and  take 

up  their  abode  in  its  tissues,  where  they  must  deyelop  further. 

Two  years  later  he  repeated  this  hypothesis   [1896]  with  the 

assistance    of    my    preliminary    researches,    but    added    some 

conjectures  as  to  the  future  fate  of  the  "  flagellated  spores." 

He  still  thought  that  mosquitos  die  on  the  surface  of  water 

a  few  days  after  laying  their  eggs  in  it.     The  malaria  germs 


4]  VARIOUS    HYPOTHESES  19 

might  now  escape  from  the  dead  insect  into  the  water,  with 
which  they  might  be  swallowed  by  men ;  or  they  might  be 
blown  about  with  the  dust  and  be  inhaled ;  and  they  might 
also  be  swallowed  by  mosquito  larvae  and  so  propagate  them- 
selves indefinitely  in  the  insects,  apart  from  man.  Roughly, 
the  life-history  of  Laveran's  bodies  was,  he  thought,  similar  to 
that  which  he  considered  Filaria  bancrofti  to  possess.  \^ 

A  few  months  later  A.  Bignami  attacked  Hanson's  views 
for  several  reasons  [1896].  He  refused  to  admit  that  mosquitos 
can  take  the  parasite  from  human  beings,  but  supposed,  con- 
versely, that  human  beings  take  it  from  mosquitos.  In  support 
of  this  he  merely  adduced  some  of  the  reasons  previously  given 
by  King.  Several  other  writers  supported  or  opposed  the 
hypothesis  about  the  same  time. 

This  is  a  short,  but,  I  think,  a  fairly  exact  account  of  these 
hypotheses.  The  importance  of  speculations  of  this  kind  is 
apt  to  be  either  underrated  or  overrated.  Modern  science  does 
not  look  upon  them  with  much  favour  unless  those  who  publish 
them  strive  also  to  verify  them.  It  is  easy  to  sit  at  home  and 
weave  many  hypotheses  ;  but  attempts  to  verify  them  generally 
demand  endless  labour,  expense,  self-sacrifice  or  even  danger, 
and  often  fail,  or,  even  if  successful,  win  little  reward.  There 
were  many  before  Columbus  who  imagined  America ;  but 
between  the  dream  and  the  reality  an  ocean  had  to  be  traversed. 
All  the  conjectures  mentioned  above  have  proved  wrong  in 
many  particulars.  Mosquitos  do  not  bring  the  virus  from  the 
marsh  to  the  man,  nor  from  the  man  to  the  marsh.  The  truth 
has  proved  to  be  far  more  wonderful  than  any  hypothesis.  It 
is  curious  that  no  one  recognised  the  suggestion  which  should 
have  been  obtained  from  the  phenomenon  of  metaxeny  amono- 
some  other  parasites,  namely,  that  the  mosquitos  might  carry 
the  virus  from  man  to  man.  I  was  driven  to  this  in  1896- 
1897  just  before  the  fact  was  revealed. 

On  the  other  hand,  such  speculations  often  serve  a  useful 
purpose   by   giving   some   direction   to   practical   work.     Thus 


20  HISTORY  [Sect. 

those  connected  with  Texas  cattle-fever,  nagana,  and  tick- 
fever  greatly  limited  the ,  labour  of  research  by  suggesting  the 
actual  species  of  the  alternative  hosts,  namely  certain  ticks  and 
tsetse  flies ;  and  those  of  Beauperthuy  and  Finlay  suggested 
the  Stegomyia  calopus  as  the  agent  of  yellow  fever.  With  regard 
to  paludism  the  earlier  hypotheses,  critically  looked  at,  suggested 
nothing  more  than  that  there  might  possibly,  or  probably,  be 
some  connection  between  mosquitos  and  the  disease.  Hanson's 
idea  regarding  these  forms  of  the  parasites  (gametocytes)  which 
produce  the  motile  filaments  (microgametes)  was,  however,  more 
than  a  mere  speculation — it  was  an  induction  based  upon  our 
general  knowledge  of  parasites.  As  he  said,  these  bodies  must 
have  some  meaning  and  object.  It  was  difficult  to  imagine  that 
they  could  have  any  other  object  except  to  infect  some  suctorial 
animal — probably  mosquitos.  But  this  idea  led  us  no  further ; 
it  gave  no  clue  as  to  how  and  where  the  parasites  live  in 
mosquitos,  how  they  return  to  man  and  infect  him,  and  in 
which  of  the  hundreds  of  species  of  mosquitos  they  exist.  It 
was  only  a  glimmer  in  the  darkness — but  it  was  something. 
Obviously  the  truth  could  be  obtained  only  by  a  long  and 
determined  investigation  of  the  whole  subject. 

"^       5.  Researches  regrarding"  the  Mode  of  Infection.— These 

really  began  with  the  old  attempts  mentioned  in  section  3  to 
find  the  infective  organism  in  marsh  water,  and  with  those 
mentioned  in  section  4,  and  culminating  in  the  negative  efforts 
of  Zeri  [1890]  to  infect  healthy  persons  with  such  water. 
Parallel  researches  on  various  worms  and  on  Piroplas7na 
bigeminuni  were  referred  to  in  the  last  section.  I  have  now 
to  describe  my  own  work.  Entering  the  Indian  Medical 
Service  in  1881  I  was  much  struck  by  the  misery  caused  among 
the  people  by  this  and  other  diseases;  and  in  1889,  during 
leave  in  England,  studied  bacteriology  and  public  health,  with 
a  view  to  undertaking  pathological  investigations.  On  return- 
ing to  India  I  was  especially  drawn  to  the  difficult  problem  of 


5]  RESEARCHES   ON    INFECTION  21 

paludism,  regarding  which  the  facts  observed  by  me  did  not 
accord  well  with  the  old  hypothesis  of  a  marsh  miasma.  I  was 
at  first  led  to  the  ideas  of  Broussais  that  the  disease  might  be 
due  to  intoxication  from  intestinal  organisms.  In  those  days 
it  was  almost  impossible  to  obtain  much  literature  in  India ; 
and  Laveran's  discovery  was  obscured  by  writers  who,  in 
attempting  to  find  his  parasites  in  the  blood,  found  only  natural 
objects  which  resembled  them.  I  detected  the  error  and,  with 
many  others,  doubted  his  discovery  in  consequence,  and  failed 
to  find  his  organism — though  I  obtained  much  valuable  practice 
in  microscopical  work.  In  1894  I  returned  to  England,  where 
P.  Manson  showed  me  the  true  Laveran's  bodies.  He  also 
told  me  his  new  mosquito  hypothesis ;  and  I  reminded  him 
that  the  same  idea  had  been  mooted  by  Laveran.  Next  year 
I  returned  again  to  India,  determined  to  work  out  the  whole 
subject  thoroughly.  The  details  have  been  previously  recorded 
in  my  Nobel  Lecture  [1905],  but  the  reader  should  know  the 
following  points. 

Little  was  then  recorded  regarding  the  structure,  habits,  or 
classification  of  mosquitos  ;  and  I  could  obtain  no  literature  on 
the  subject,  and  was  obliged  to  find  out  everything,  including 
the  technics,  for  myself.  I  was  not  then  aware  of  the  specula- 
tions of  Beauperthuy,  Finlay  and  King,  or  the  discovery  of 
Smith  and  Kilborne. 

There  was  nothing  to  guide  me  as  to  the  species  of  mosquito 
concerned,  as  we  had  no  right  to  assume  that  the  malaria- 
bearing  species  is  necessarily  the  commonest  in  any  malarious 
locality ;  and  as  metaxeny  was  not  known  at  that  time  among 
unicellular  parasites  of  animals,  there  was  nothing  to  indicate 
the  form  or  position  that  Laveran's  bodies  would,  by  supposition 
take  in  the  insects.  The  study  of  these  minute  organisms  was 
moreover  much  more  difficult  than  that  of  the  large  worms 
already  investigated  ;  and  the  proper  method  of  staining  was 
not  then  known. 

In  May  1895  I  fed  Ciilex  and  Stego7iiyia,hxQ^  from  the  larva 


22  HISTORY  [Sect. 

on  patients  with  the  gametids  (crescents)  in  their  blood,  and 
showed  that  the  motile  filaments  were,  as  usual,  extruded  in  the 
insects'  stomachs.  But  I  speedily  found  that,  owing  to  their 
minute  and  delicate  structure,  it  was  impossible  to  follow  them 
further,  as  Manson  had  suggested  should  be  done.  I  was 
therefore  obliged  to  adopt  a  new  procedure  of  my  own.  The 
insects  were  kept  alive  after  being  fed  for  several  days,  and 
were  then  exhaustively  searched  for  any  parasites  they  might 
contain.  If  such  parasites  were  found  it  was  possible  that  they 
might  be  the  developed  motile  filaments  ;  and  the  point  could 
be  cleared  up  by  subsequent  experiments.  This  method  was 
extremely  laborious,  but  was  the  only  one  possible.  For  more 
than  two  years  the  results  were  completely  negative. 

Meantime,  following  the  later  conjectures  of  Manson,  I  tried 
to  infect  healthy  persons  by  giving  them  to  drink  water  in 
which  fed  mosquitos  had  died.  By  some  accident  the  first 
case  appeared  successful ;  but  twenty-one  succeeding  experi- 
ments practically  failed  [1896]. 

For  this  and  other  reasons  I  abandoned  this  part  of  Manson's 
hypothesis,  and  began  to  think  that  the  insects  probably  carry 
the  parasites  from  man  to  man,  either  depositing  them  by 
defaecation  on  the  skin  of  healthy  persons,  or  inoculating  them 
under  the  skin  after  puncture.  In  August  1896,  Mr  Appia, 
Assistant  Surgeon  of  the  Civil  Hospital  at  Bangalore,  kindly 
submitted  to  the  suggested  experiments.  Many  Stegomyia 
and  Ctilex,  previously  fed  on  patients,  were  fed  on  him  a  few 
days  later.  There  was  no  result — the  mosquitos  being  of  the 
wrong  species,  and  the  period  between  the  feedings  being  too 
short  [1896]. 

Bignami  now  criticised  Manson's  hypothesis  [1896];  but  I 
made  a  number  of  experiments  in  support  of  it,  and  showed 
that  the  extrusion  of  the  motile  filaments  is  really  a  living 
process  and  not  a  "death  agony"  as  many  had  thought  [1897]. 

My  repeq,ted  failures,  however,  now  persuaded  me  that  I 
had  probably  been  working  with  the  wrong  kinds  of  mosquitos  — 


5] 


RESEARCHES   ON    INFECTION 


23 


Culex  and  Stegomyia ;  and  in  April  1897  ^  went  to  an  intensely 
malarious  spot  near  Ootacamund  in  the  Nilgiri  mountains,  in 
order  to  see  if  I  could  find  another  likely  kind.  There,  for  the 
first  time,  I  saw  an  Anopheline — the  really  culpable  kind  ;  and 
also  made  several  observations  which  made  me  finally  abandon 
the  second  part  of  Manson's  hypothesis  and  adopt  the  view  that 
the  insects  carry  the  parasites  in  some  way  from  man  to 
man  [1898]. 

A  few  months  later  I  returned  to  Secunderabad,  where  I 
had  commenced  my  mosquito  work  in  1895,  and  was  at  last 
rewarded  with  success.  On  the  20th  and  21st  August  I  found 
the  zygotes  of  the  parasites  in  two  large  dapple  -  winged 
mosquitos  which  had  been  bred  from  the  larva,  and  fed  on 
a  case  containing  crescents.  This  fortunate  observation  gave 
the  clue  to  all  that  followed,  because  it  indicated  the  form 
and  position  of  the  parasite  in  the  insect,  and  also  the  variety 
of  insect  capable  of  carrying  it.  The  problem  was  practically 
solved,  and  only  details  and  formal  proofs  required  to  be 
ascertained. 


Figure  i. 


.*.         •  '    '% 


•■        '•       .*      .' 


i4  HISTORY  [Sect. 

The  matter  was  reported  at  once  to  Government,  and  the 
medical  press  [1897].  Unfortunately  no  more  of  the  large 
dapple-winged  mosquitos  could  be  obtained,  but  I  found  the 
pigmented  cells  in  a  Culex  which  had  been  caught  feeding  on 
a  case  of  tertian  malaria,  and  also  in  one  of  a  smaller  kind 
of  dapple  -  winged  mosquito.  On  this  I  wrote  to  Manson 
telling  him  to  expect  the  full  solution  of  the  problem  in  a 
few  weeks.  Next  day,  however,  I  was  ordered  to  proceed  to 
Kherwara,  a  place  a  thousand  miles  distant,  where  there  was 
little  malaria  at  the  time.  Owing  to  this  interruption  I  have 
never  been  able  to  identify  exactly  the  two  species  of  dapple- 
winged  mosquitos ;  but  from  their  general  characters,  the 
markings  on  their  wings  and  the  shape  of  their  ^%^'s>,  they 
were  obviously  Anophelines. 

I  remained  at  Kherwara  from  September  1897  to  February 
1898,  when  the  Government  was  good  enough  to  put  me  on 
special  duty  to  continue  my  researches  in  Calcutta.  On  arrival 
there  I  found  it  impossible  to  work  with  human  malaria, 
chiefly  on  account  of  the  riots  caused  by  Mr  Haffkine's 
anti  -  plague  inoculation,  and  therefore  attacked  the  malaria 
of  birds. 

According  to  Hanson's  hypothesis,  the  motile  filaments 
were  flagellated  spores  capable  of  living  in  mosquitos'  tissues  ; 
but  my  pigmented  cells  contained  plasmodin,  which  cannot 
exist  in  spores.  The  discrepancy  was  explained  by  a  series 
of  researches  made  in  1896,  Metchnikoff  and  Simond  had 
found  similar  motile  filaments  in  Coccidiuni  oviforvie  of  rabbits, 
and  suggested  that  they  are  really  sperms  and  not  spores  [1897]  J 
and  a  little  later  MacCallum' and  Opie  in  America  actually 
observed,  in  the  case  of  one  of  the  malaria  parasites  of  birds 
{Halteridmm)  and  one  of  those  of  men,  these  sperms  in  the 
act  of  fertilising  the  female  cell  [1897].  My  pigmented  cells 
were  therefore  the  fertilised  cells,  or  zygotes,  still  carrying  the 
plasmodin  which  they  originally  possessed. 

In  March  1^8,  I  found  these  bodies  again  in  Culex fatigans 


5]  RESEARCHES    ON    INFECTION  25 

fed  on  birds  containing  Plasmodium  {Proteosomd)  danilevskyi. 
In  a  few  months,  by  means  of  rigid  experiments,  the  develop- 
ment of  the  parasites  in  the  insects  was  fully  ascertained.  On 
the  4th  July  I  observed  the  extraordinary  fact  that  the  proto- 
spores  (sporozoites)  of  the  parasites  enter  the  insects'  salivary  or 
poison  glands,  thus  suggesting  that  infection  is  produced  by  the 
bites  of  the  insects.  I  had  thought  that  this  might  be  the  case, 
but  none  of  us  had  ever  really  imagined  such  a  wonderful  process 
— nature  surpassed  the  divination  of  all  of  us!  In  July  and 
August  I  infected  twenty-two  out  of  twenty-eight  healthy 
sparrows  and  some  other  birds,  by  means  of  the  bites  of  Culex 
fatigans  which  had  been  previously  fed  on  infected  birds. 

These  experiments  gave  the  fundamental  solution  of  the 
problem,  and  the  first  proof  of  metaxeny  among  unicellular 
parasites  of  animals — just  as  Kiichenmeister's  had  proved  the 
process  to  hold  for  higher  organisma.  They  exhibited,  with 
the  assistance  of  MacCallum  and  Opie's  observation,  the  whole 
development,  step  by  step  —  the  position  and  form  of  the 
parasites  in  mosquitos,  and  the  wonderful  method  of  infection. 
Owing  to  the  great  similarity  of  the  avian  and  human  parasites, 
there  was  no  doubt  that  the  latter  had  the  same  history — and 
indeed  the  stages  of  these  up  to  the  fifth  day  had  already  been 
found  by  me  a  year  previously  in  Anophelines. 

I  was  now  anxious  to  complete  the  work  on  human  malaria, 
but  was  ordered  to  leave  the  subject  and  attack  the  difficult  one 
of  kala-azar.  This,  with  the  writing  of  the  necessary  report, 
occupied  me  for  nearly  six  months,  until  I  left  India  in 
February  1899.  I  then  joined  the  newly-formed  Liverpool 
School  of  Tropical  Medicine ;  and  at  the  end  of  July  set  out 
with  E.  E.  Austen,  Entomologist  at  the  British  Museum, 
and  Dr  H.  E.  Annett,  of  our  School,  to  complete  my  study 
of  the  human  parasites.  In  a  few  weeks  I  was  able  to  show 
that  the  parasites  of  quartan,  tertian,  and  malignant  fever  all 
develop  in  Pyretophorus  cos  talis  or  Myzomyia  funesta,  precisely 
as  the  Proteosoma  of  birds  develops  in   Culex  fatigans.     This 


26  HISTORY  [Sect. 

completed    the    task  ;    and     I    now    turned    to    the    subject    of 
practical  prevention. 

6.  Confirmations  and  Extensions. — My  observations  of  the 
parasites  in  mosquitos  were  published  by  myself  in  a  series  of 
papers  on  i8th  December  1897,  26th  February  1898,  21st  May 
1898,  nth  October  1898,  and  24th  January  1899  ;  and  also,  owing 
to  official  delay  in  regard  to  some  of  my  reports,  by  Manson  on 
1 8th  June  1898,  July,  and  24th  September  1898.  My  paper 
[May  1898]  contained  a  full  account  with  plates  of  the  necessary 
technique  invented  by  myself,  and  of  the  stages  of  Proteosonia 
in  the  mosquito  up  to  the  sporulation  of  the  zygotes — the  mode 
of  infection  being  published  in  the  later  papers  by  Manson  (to 
whom  I  had  telegraphed  the  news  in  time  for  the  Annual  Meet- 
ing of  the  British  Medical  Association  at  the  end  of  July),  and 
also  by  myself  [October  1898].  Moreover,  I  had  sent  numbers 
of  my  specimens  to  him  and  to  Laveran  ;  and,  in  fact,  by  August 
1898  my  researches  were  well  known  to  most  workers  at  the 
subject  in  Europe  and  America. 

The  first  to  confirm  them  was  R.  Koch,  with  Kossel,  who 
in  September  followed  completely  the  development  of  Pro- 
teosoma  in  Culex  ne^iiorosus,  and  demonstrated  a  point  which  I 
had  not  had  time  to  deal  with,  namely,  how  the  zygotes  traverse 
the  wall  of  the  insect's  stomach  [1899]. 

In  December,  C.  Daniels,  sent  by  the  Royal  Society  to 
examine  my  results,  arrived  in  Calcutta  and  confirmed  them 
[1899].  He  and  Dr  Rivenberg  also  assisted  me  greatly  at  that 
time. 

Until  my  researches  were  published,  the  Italian  writers  had 
generally  disbelieved  in  the  mosquito  hypothesis,  though  A. 
Bignami  had  accepted  it  on  the  lines  of  Lancisi  and  King. 
Now,  however,  they  made  strenuous  efforts  to  follow ;  but  they 
reached  no  tangible  result  until  November,  when  Bignami,  in 
the  light  of  my  experiments  on  birds,  infected  a  man  in  Rome 
with  mosquitos  brought  from  Maccarese  [November  1898].     A 


6]  CONFIRMATIONS    AND    EXTENSIONS  27 

few  weeks  later  A,  Bignami,  G.  Bastianelli  and  B.  Grassi  found 
the  zygotes  of  malignant  malaria  in  Anopheles  maculipennis, 
fifteen  months  after  my  original  success  with  the  same  parasite 
in  Secunderabad,  and  four  months  after  the  whole  life-cycle  of 
the  parasites,  as  exemplified  in  Proteosoma,  had  been  fully 
published  by  Manson  and  myself  They  were  thus  able  to 
forestall  the  completion  of  my  work  on  the  human  parasites, 
but  did  so  entirely  by  following  my  previous  researches,  while 
my  time  was  being  wasted  over  a  lengthy  report  on  kala-azar — 
a  duty  which  I  was  not  permitted  to  postpone.  Being  very 
favourably  placed  for  the  work,  and  not  being  subject  as  I  was 
to  interruptions,  they  succeeded  in  infecting  three  more  persons, 
and  were  able  to  publish  numerous  papers  with  coloured 
pictures,  which  greatly  popularised  the  subject.  They  proved 
one  important  new  fact,  however — that  the  tertian  parasites 
also  are  carried  by  the  Anophelines  ;  and  I  verified  this  later 
in  Sierra  Leone.^ 

^  The  relations  between  the  work  of  these  authors  and  of  myself  are  exactly  dis- 
cussed in  my  lecture  [1905].  For  a  long  time  some  writers  attributed  to  them  the 
discovery  of  the  mosquito-cycle  of  the  important  human  parasites,  and  to  me  only 
the  study  of  the  humble  Proieosoma  of  birds.  But  according  to  zoological  rules, 
priority  in  the  discovery  of  the  life-history  of  any  group  of  organisms  belongs  to 
that  investigation  which  first  discloses  the  new  life-history  in  any  member  of  the 
group — which  is  only  just,  since  there  is  usually  little  difficulty  in  repeating  the  same 
observations  for  other  members  of  the  group.  The  life-history  of  Proteosoma  there- 
fore holds  the  priority  in  the  case  of  all  similar  life-histories ;  and  is  in  fact  identical 
with  those  of  the  human  parasites,  and  indeed  almost  the  same  as  those,  since  found, 
of  other  unicellular  organisms.  Efforts  were  also  made,  with  the  same  object,  to  dis- 
credit my  original  successes  of  1S97  with  the  human  malignant  parasites  by  the 
statement,  contrary  to  the  printed  evidence  of  my  words  [December  1897],  that  the 
mosquitos  used  by  me  had  not  been  bred  from  the  larvae — although  the  men  who 
made  these  efforts  were  apparently  actually  committing  at  the  time  the  very  fault  of 
which  they  wrongly  accused  me.  In  a  later  work  B.  Grassi  occupied  many  pages 
in  trying  to  persuade  the  world  that  he  had  discovered  the  "  Anopheles  malariferi 
indipendentemente  da  Ross"  [1900,  p.  31].  Unfortunately  for  him  he  had  referred 
to  my  work  in  a  paper  [October  1898]  which  he  had  published  two  months  before 
he  "discovered"  anything  at  all.  There  is  no  doubt  that  he  and  his  colleagues 
recognised  the  genus  of  my  "dapple-winged"  mosquitos  from  several  statements  of 
mine,  and  were  thus  able  easily  to  find  the  parasites  in  members  of  the  same  group  in 
Italy.  The  Italian  work  was  due  mainly  to  Bignami  and  Bastianelli,  and  not  to  this 
author  as  erroneously  stated  in  many  monographs  and  articles.  Laveran  has  made 
similar  remarks  about  his  own  work  [1907,  p.  13J ;  and  the  matter  is  mentioned  here 
because  such  misstatements  are  apt  to  discourage  genuine  work  [Ross,  1905]. 


28  HISTORY  .,  ^[Sect. 

In  November  1899,  I^-  Koch,  who  has  given  suclT  great 
discoveries  to  pathology,  added  another  in  connection  with 
malaria.  He  found  in  the  valley  of  Ambawara  in  Java  that 
while  large  numbers  of  the  native  children  showed  the  parasites 
in  their  blood,  the  adults  seemed  to  be  comparatively  free  from 
them,  and  had  obviously  become  partially  immune.  Thus  in 
most  very  malarious  places  it  is  chiefly  the  children  who 
suffer  from  the  acute  disease.  The  blood  of  those  who  survive 
gradually  produces  something  which  after  a  number  of  years 
has  the  power  of  reducing  and  perhaps  extinguishing  the 
parasite  invasion.  From  this  it  follows  that  in  such  localities 
the  Anophelines  must  become  infected  principally  from  the 
native  children  {see  section  31  (9)). 

In  the  summer  of  1900,  P.  Manson  carried  out  an  important 
crucial  experiment.  A  number  of  Anopheles  maculipennis,  fed 
on  cases  of  mild  tertian,  were  brought  from  Italy  to  London, 
and  were  allowed  to  bite  P.  T.  Manson  there  on  several 
occasions.  He  developed  the  disease  on  the  13th  September, 
the  tertian  parasites  being  found  in  his  blood  a  little  later. 
The  insects  were  also  allowed  to  bite  G.  Warren,  who  was 
similarly  attacked  fourteen  days  afterwards.  At  the  same 
time  L.  Sambon,  G.  C.  Low  and  two  others  lived  for  three 
of  the  most  malarious  months  in  one  of  the  deadliest  places 
in  the  Roman  Campagna,  Ostia,  without  contracting  the 
disease,  because  they  spent  the  nights  in  a  hut  protected  by 
wire  gauze  against  the  entry  of  mosquitos. 

On  many  other  occasions  healthy  persons  have  been 
similarly  infected  on  the  lines  of  my  experiments  with  birds 
in  July  to  August  1898.  As  already  mentioned  Bignami  and 
Bastianelli  infected  four  persons  in  Rome  (which  is  itself  free 
from  malaria)  in  1898- 1899.  Subsequently  C.  F.  Fearnside  at 
Rajamundri  in  India  infected  seven  out  of  eight  persons, 
including  himself,  in  1900-1901  [1901].  W.  Schiiffner  infected 
himself  and  two  others  at  Delhi,  Sumatra,  in  August  and 
September    1901,  two   with    tertian   and    one   with    malignant 


7]  PREVENTION  29 

malaria,  by  means  of  certain  Anophelines  [1902].  N.  Jancso 
infected  ten  out  of  fifteen  persons  at  Kolozsvar  in  Hungary 
in   1904  by  means  of  A.  maculipennis  (section   17). 

My  work  on  the  Proteosoma  of  birds  has  been  confirmed 
by  Koch  [1899],  C.  Daniels  [1899],  B.  Grassi  [1900],  R.  Ruge 
[1901],   Ed.   and   Et.  Sergent   [1907],   R.  O.  Neumann   [1908]. 

The  mosquito  cycle  of  the  human  parasites  has  been  further 
worked  upon  by  Fernside  [1901],  Stephens  and  Christophers 
[1899-1903],  Schiiffner  [1902],  Jancso  [1904],  Schaudinn  and 
others. 

Reviewing  this  history  we  shall  see  that  the  great  stream 
of  research  on  malaria,  descending  to  us  through  more  than 
two  thousand  years,  is  composed  of  three  main  tributaries 
finally  mingled  together.  One  tributary  rises  in  the  work  of 
the  ancients  on  the  different  clinical  forms,  and  consists  of 
the  discovery  of  the  cinchona  bark  ;  the  work  of  Torti  (1753)  ; 
the  discovery  of  the  plasmodin  by  Meckel  (1847);  of  the 
parasites  by  Laveran  (1880);  and  of  the  confirmations  and 
extensions  of  Golgi,  Danilewsky  and  many  others. 

Another  tributary  consists  of  the  ancient  observations  con- 
necting the  disease  with  marshes  ;  the  speculations  of  Varro, 
Columella,  Lancisi,  Beauperthuy,  King,  Laveran,  Koch  and 
Manson  ;  and  the  valuable  researches  of  those  who  tried  to 
find  the  organism  in  marshes. 

The  third  tributary  consists  of  the  early  work  on  para- 
sites;  the  discovery  of  metaxeny  by  Abildgaard  (1790), 
Steenstrup  (1842),  and  Kiichenmeister  (1851);  the  discoveries 
of  Leukart,  Fedschenko  (1858),  Melnikoff  (1868),  Manson 
(1877),  regarding  certain  worms;  that  of  Smith  and  Kilborne 
(1889)  regarding  Piroplasma ;  of  Bruce  on  trypanosomes  my 
work  on  human  and  avian  malaria  (1895 -1899);  and  the 
confirmations  and  extensions  which  followed. 

7.  Recent  History  of  Prevention. — It  is  open  to  question 
whether   the   extensive   drainage   works   of   the   ancients   had 


30  HISTORY  [Sfxt. 

been  carried  out  for  sanitary  or  for  agricultural  purposes ; 
but  there  is  no  doubt  that  for  several  centuries  the  Italians, 
and  other  nations,  have  known  how  to  control  malaria  by 
drainage  and  allied  measures.  In  fact,  for  a  long  time  the  state- 
ment that  drainage  reduces  malaria  has  been  generally  accepted 
as  a  medical  dogma.  As  soon  as  the  mosquito  theorem  began 
to  become  consolidated,  the  question  arose  whether  the  new 
knowledge  would  not  provide  us  with  some  easier  and  cheaper 
method  of  prevention.  My  own  studies  had  been  undertaken 
principally  for  this  object ;  and  the  following  observations 
of  mine  were  connected  with  it. 

As  early  as  1884-1885  in  Bangalore,  and  many  times  since 
then,  I  had  noticed  that  Stegomyia  and  Culex  could  be  largely 
reduced  in  numbers  in  my  own  house  by  emptying  out  the 
stale  rain-water  collected  in  tubs  and  pots  in  the  garden. 
On  one  occasion  I  offered  to  reduce  these  mosquitos  in  the 
regimental  mess  -  house,  but  the  adjutant  objected  because, 
he  said,  I  should  be  disturbing  the  order  of  nature !  But  I 
satisfied  myself  as  to  the  possibility  of  making  such  a  reduction 
by  my  own  personal  experiences  in  many  parts  of  India. 

After  incriminating  my  dapple  -  winged  mosquitos  (Ano- 
phelines)  in  Secunderabad  in  1897  I  studied  .their  habits 
there  and  in  Kherwara,  Calcutta,  the  Darjeeling  Himalaya 
region,  and  Assam,^  and  noted  the  following  points. 
»  The  eggs  of  the  Anophelines  were  more  or  less  boat-shaped, 
and  possessed  a  peculiar  membrane  which  gave  them  the 
appearance  of  having  a  row  of  oars  on  either  side  —  thus 
differing  from  the  eggs  of  the  Culex  and  Stegomyia.  They 
were  also  apt  to  arrange  themselves  in  triangular  patterns  on 
the  surface  of  the  water.  The  larvae  floated  flat  on  the  surface 
and  had  no  long  breathing  tube — being  thus  unlike  those  of  the 
other  common  groups.  The  adults  were  generally  differentiated 
by  having  spotted   (dappled)  wings  ;   a  shape  more  suited  for 

1  I  could  obtain  no  information  on  mosquitos  in  India  at  that  time,  not  even  at 
the  Indian  Museum  in  Calcutta. 


7]  PREVENTION  31 

long  flight ;  and  a  peculiar  attitude,  when  resting,  at  an  angle 
to  the  surface  to  which  they  clung.  These  points  would  enable 
any  one,  even  uneducated  labourers,  to  distinguish  them.  But 
above  all,  my  native  assistants  and  myself  noticed  everywhere 
that  the  larvae  do  not  generally  breed  in  the  pots  and  tubs 
occupied  by  those  of  the  other  groups,  but  mostly  in  pools  of 
water  on  the  ground.  This  led  me  at  once  (1897)  to  the 
explanation  of  the  central  fact  that  malaria  is  connected  with 
marshes.  If  Culex  and  Stegomyia  had  been  responsible  for  the 
disease  it  would  not  have  possessed  this  relation — it  would  have 
been  connected  with  pots  and  tubs,  etc.,  just  as  yellow  fever, 
which  is  carried  by  Stegomyia,  is  connected  with  them.  1  did  not 
then  know  that  the  quartan  and  tertian  parasites  are  also  carried 
by  Anophelines,  but  guessed,  from  the  well  -  known  relation 
referred  to,  that  they  were  carried  by  some  kind  of  marsh-breed- 
ing gnats,  and  not  by  the  pot-breeding  ones.  The  explanation 
was  now  clear ;  the  ancients  were  quite  right — the  disease  is 
caused  by  an  emanation  from  the  marsh.  That  emanation,  how- 
ever, is  not  a  gas,  nor  even  a  contagimn  vivum,  but  an  insect. 

It  was  observed  also  that  the  Anophelines  do  not  breed 
so  much  in  large  open  bodies  of  water,  such  as  lakes,  rivers 
and  reservoirs,  but  more  in  small,  shallow,  and  often  grassy 
pools  and  puddles  where  they  can  obtain  shelter  from  wind 
and  fish  ;  and  that  like  other  mosquitos,  they  abound  most  in 
proximity  to  their  breeding  -  places.  Putting  all  these  facts 
together,  I  reasoned  that  we  now  possessed  a  much  cheaper 
and  easier  method  of  prevention.  Previously,  we  had  been 
obliged  to  drain  a  whole  area  at  great  cost  ■  now  we  should 
be  able  actually  to  seek  out  and  determine  the  exact  malaria- 
producing  pools,  namely,  those  which  contain  the  larvae,  and 
then  to  fill  up  or  drain  these  alone ;  and  I  naturally  inferred 
that  if  the  old  method  had  been  feasible  (as  it  had  been  in 
many  places),  the  new  method  would  be  still  more  easily 
feasible,  and  at  less  expense. 

Before  leaving  India  I  described  my  proposals  in  a  short  report 


32  HISTORY  [Sect. 

to  Government,  dated  the  i6th  February  1899,  and  published 
five  months  later  without  date,  and  with  a  title  given  apparently 
by  the  editor  [1899].  The  matter  is  so  important,  and  my 
views  have  been  so  much  misreported,  that  I  must  reiterate 
exactly  what  I  said.  I  pointed  out  that  mosquitos  in  general 
"  are  seldom  to  be  found  in  the  larger  bodies  of  water  "  ;  that 
to  get  rid  of  them  locally  "  it  will  suffice  to  empty  out  or  drain 
away  or  treat  with  certain  chemicals  the  small  collections  of 
water "  in  which  they  breed  ;  that  the  Anophelines  "  seem  to 
choose  only  rain-water  puddles  and  ponds  too  large  to  dry 
up  under  a  week  or  more,  and  too  small  or  too  foul  and  stagnant 
for  minnows."  I  said  that  such  pools  "are  not  common  in 
most  parts  of  India  except  during  the  rains,"  and  "seem  to  be 
so  isolated  and  small  that  I  think  it  may  be  possible  to 
exterminate  this  species  under  certain  circumstances."  I  added, 
however,  that  "  I  wish  to  be  understood  as  writing  with  all 
due  caution  on  these  points."  "  I  limit  this  statement  to  certain 
localities  only,  because  it  is  obvious  that  where  the  breeding- 
pools  are  very  numerous,  as  in  water-logged  country,  or  where 
the  inhabitants  are  not  sufficiently  advanced  to  take  the  neces- 
sary precautions,  we  can  scarcely  expect  the  recent  observations 
to  be  of  much  use — at  least  for  some  years  to  come.  And  this 
limitation  must,  I  fear,  exclude  most  of  the  rural  areas  in  India. 
Where,  however,  the  breeding  -  pools  are  not  very  numerous, 
and  where  there  is  anything  approaching  a  competent  sanitary 
establishment,  we  may,  I  think,  hope  to  reap  the  benefit.  .  .  . 
And  this  should  apply  to  the  most  crowded  areas,  such  as  those 
of  cities,  towns  and  cantonments,  and  also  to  tea,  coffee  and 
indigo  estates,  and  perhaps  to  military  camps."  "  In  making 
these  suggestions  I  do  not  wish  to  excite  hopes  which  may 
ultimately  prove  to  have  been  unfounded."  I  concluded  by 
urging  further  investigations  on  the  malaria-bearing  mosquitos 
of  India  and  their  habits.  Though  the  report,  being  hurriedly 
written,  might  have  been  more  exactly  expressed  in  places,  it 
is  correct  enough. 


7]  MOSQUITO   REDUCTION  33 

As  it  was  the  original  statement  of  the  radical  anti-malaria 

measure — which  has  since  been  used  with  success  in  many  parts 

of  the  world,  and  will  certainly  be  adopted  in  the  future  as  a 

fundamental  principle  of  tropical  urban  sanitation — the  reader 

should  now  clearly  grasp  what  exactly  was  proposed.     Animals 

tend    to    abound    most    where   the   local    conditions   are   most 

favourable   to   them.     Conversely,   if  we   can    make   the   local 

conditions    unfavourable,  they  should  become   less   numerous. 

Also,  malaria  being  carried  by  certain  Anophelines,  should,  as 

a   broad  general  principle,  be   most   common  where   they  are 

most  common,  and  should  be  reduced  where  they  are  reduced. 

I    proposed,  therefore,  to   reduce   their  numbers   by  measures   I 

directed  against  their  breeding-places.     But  this  proposal  was 

obviously  not  meant  to  apply  to  the  whole  world,  but  only  to 

places  where  the  measures  were  most  likely  to  be  feasible — that 

is,  generally  to  "  crowded  areas,"  and  not  to  "  rural  areas."     A 

square  mile  of  town,  containing  thousands  of  ratepayers,  may 

be  assumed  to  have  money  available  for  such  work  ;  while  open 

country,  containing  perhaps  only  a  few  scattered   houses,  has 

no   such  funds.     Moreover,  mosquito-reduction  in  a  town  will 

benefit  thousands  of  people,  while  in  the  country  it  will  benefit 

only  a  few — and  that  for  the  same  cost.     An  identical  principle 

applies    to  pipe  water-supply  and  to  pipe-sewerage  systems — 

these   are  frequently  given    to   towns,  but  not  so   often,  even 

in  Europe,  to  widely-scattered  farmhouses.     If  then,  I  argued 

in  effect,  a  town  can  afford  to  provide  its  inhabitants  with  a 

piped  water-supply,  or  a  sewerage  system,  it  ought  also  to  be 

able  to  keep  them  free,  partially  at  least,  from  such  dangerous 

insects    as    mosquitos.      At    that    time    I    had    had    a    rather 

exceptional   experience    of    practical    sanitation,    having   been 

specially  appointed  by  the  Government  of  India  to  improve 

the  sanitation  of  a  large  Indian  town  (Bangalore),  and  I  knew 

what  I  was  writing  about.     As  a  general  rule  it  would  be  much 

cheaper,  I  thought — and  probably  every  practical  engineer  or 

health  officer  will  agree  with  me — to  make  a  great  reduction 


34  HISTORY  [Sect. 

of  mosquitos  in  most  towns,  than  to  instal  and  maintain  a 
piped  water-supply  or  sewerage  system.  I  held  also — and  still 
hold — that  the  same  measures  might  be  feasible  in  some  cases, 
even  in  plantations,  military  camps  and  villages.^ 

Unfortunately  there  are  many  people  who  seem  to  regard 
any  new  idea  as  a  personal  affront — who  never  try  to  under- 
stand the  author,  who  disregard  his  reservations,  and  who 
attribute  to  him  any  absurd  opinion !  I  was  immediately 
accused  of  proposing  to  destroy  every  mosquito  throughout 
India  and  Africa,  and  of  trying  to  upset  the  order  of  nature, 
and  so  on.  Still  worse,  many  others  accepted  this  idea  without 
understanding  the  practical  details,  and  did  much  harm  by 
attempting  the  work  in  quite  unsuitable  places.  Lastly,  some 
rejected  the  idea,  but  pretended  to  test  it  experimentally — and 
of  course  failed. 

In  1899,  owing  to  the  efforts  of  a  number  of  medical 
men  and  men  of  affairs,  and  largely  to  the  recent  work 
on  malaria,  schools  of  tropical  medicine  were  opened  in 
Liverpool  and  London.  At  my  inaugural  lecture  at  the  former 
(published  at  the  same  time  as  the  previous  paper)  I  repeated 
the  same  suggestions  [1899].  Judging  from  my  Indian  experi- 
ences, I  overrated  somewhat  the  difficulty  of  reducing  Culicines  ; 
but  concluded  by  invoking  experiments  on  such  points. 

West  Africa,  a  great  country  hitherto  paralysed  by  malaria, 
had  long  attracted  me  as  an  objective  for  practical  preventive 
work,  and  I  dreamed  that  it  might  be  revolutionised  by  it. 
Hence,  no  sooner  was  the  Liverpool  School  of  Tropical 
Medicine  opened,  than  I  proposed  to  the  Committee  that  I 
should  be  sent  there  to  study  the  subject  in  detail.  Conse- 
quently I  left  England  in  July  (1899)  with  Dr  H,  E.  Annett 
of  the  School,  and  Mr  E.  E.  Austen  of  the  entomological 
department  of  the  British  Museum,  to  see  what  could  be  done 
in  Freetown,  the  capital  of  Sierra  Leone — long  known  as  the 

1  Malcolm  Watson  (section  57)  is  now  extending  Anopheline  reduction  to  rural 
areas  as  well  as  towns.     See  also  sections  42  and  43. 


7]  MOSQUITO   REDUCTION  35 

"white  man's  grave."  As  already  stated  (section  5)  we  quickly 
incriminated  two  local  Anophelines,  P.  costalis  and  Myzomyia 
funesta,  as  carriers  of  malaria  ;  and  then  set  out  to  study  their 
habits  with  a  view  to  elaborating  the  principle  of  mosquito- 
reduction  for  practical  sanitation. 

Before  we  left  it  was  arranged  that  our  work  should  be 
published  anonymously  in  the  medical  press  as  promptly  as 
possible  for  the  guidance  of  others ;  and  I  consequently  wrote 
a  series  of  four  articles  which  were  published  in  the  British 
Medical  Journal  in  September  and  October  [1899.]  The  first 
two  of  them  described  the  finding  of  the  carriers  ;  but  the  two 
latter  (30th  September,  p.  869,  and  14th  October,  p.  1033) 
gave  the  leading  points  in  the  habits  of  the  Anophelines,  the 
broad  distinctions  between  them  and  the  Culicines,  the  nature 
and  distribution  of  their  breeding  pools,  and  other  matters 
connected  with  the  general  theory  of  malaria,  together  with 
a  plate  showing  the  characteristic  attitude,  and  one  showing 
a  characteristic  breeding  -  pool.  In  all  these  points  these 
Anophelines  of  Sierra  Leone  proved  to  be  generally  similar 
to  those  which  I  had  studied  in  India.  The  articles  drew  wide 
attention  to  the  subject ;  and  in  fact  formed  the  basis  of  work 
on  the  reduction  of  mosquitos  for  malaria  done  since  then  ; 
though,  being  anonymous,  they  are  not  often  referred  to  in 
the  literature  of  the  subject.^ 

Being  obliged  to  hurry  back,  we  could  spend  only  seven 
weeks  in  the  Colony ;  and,  as  we  were  only  private  individuals, 
we  could  not  carry  out  our  recommendations.  In  February 
1900  we  published  our  report ;  in  the  main  body  of  which  I 
summed  up  my  results  and  recommendations  with  plates  and 
figures.  Operations  for  reducing  the  Anophelines  were  divided 
into  those  meant  to  prevent  their  breeding,  such   as  draining 

^  In  1899,  G.  H.  F.  Nuttall  resuscitated  some  older  works  about  mosquito-reduction. 
C.  Finlay  and  A.  F.  A.  King  had  recommended  it  hypothetically,  and  C.  B.  Aaron, 
L.  O.  Howard  and  others  did  practical  experiments  with  oil,  and  other  agencies ;  but 
these  attempts  (of  which  I  was  ignorant)  do  not  constitute  anything  like  the  practical 
sanitary  policy  drawn  up  by  me. 


36  HISTORY  [Sect- 

or  filling  the  pools  or  treating  them  with  Culicicides  (oil,  tar, 
lime,  etc.) ;  and  the  destruction  of  the  adults  or  larvae.  I 
devoted  a  whole  section  to  discussing  the  local  conditions 
under  which  such  operations  were  likely  to  be  successful,  and 
concluded  as  follows  : — 

"(i)  Operations  against  Anopheles  are  least  likely  to  be 
effectual  in  level,  water-logged  localities,  and  in  places  where 
the  insects  breed  in  pools  which  cannot  easily  be  found,  or 
cannot  easily  be  treated.  (2)  Operations  will  probably  be 
easier  in  country  which  is  not  quite  level,  or  where  the  rain- 
fall is  not  great.  (3)  They  promise  to  be  very  easy  in  extremely 
dry  places.  Lastly,  it  goes  without  saying  that  we  can  scarcely 
ever  attempt  to  deal  with  Anopheles  in  large  rural  areas.  On 
the  other  hand,  we  may  reasonably  hope  to  reduce  them,  if 
not  to  exterminate  them,  in  the  principal  centres  of  population 
and  civilisation — that  is,  just  in  the  places  where  the  prevention 
of  malaria  would  be  most  useful — provided  always  that  we 
make  intelligent  and  persistent  efforts  to  do  so."  Also,  both 
in  this  report  and  in  a  previous  small  book  of  instructions 
for  laymen  [1899],  I  dxscwssed  personal  prophylaxis  by  the  use 
of  mosquito  nets,  etc.,  and  the  reduction  of  Culicines  round 
houses ;  and  I  also  pointed  out  how  much  Europeans  in  Africa 
suffered  from  not  being  segregated  from  the  natives  as  they 
are  in   India  [February   1900,  p.   45].^ 

I  have  described  these  thoughts  and  studies  at  some  length, 
because  they  constitute  the  conclusion  of  my  work  commenced 
five  years  previously,  long  before  others  had  considered  the 
matter  worth  touching,  and  therefore  have,  I  think,  the  right  of 
priority.  But,  as  I  have  already  stated,  immediately  after  the 
publications  of  my  work  in  the  middle  of  1898,  numbers  of 
medical  men  and  naturalists  began  to  take  up  the  matter  in 
many  parts  of  the  world.     The  classification  and  habits  of  the 

1  I  said  also  on  the  same  page  that  a  single  intelligent  native  agent  might  "do  a 
great  deal  of  good  "  as  regards  the  reduction  of  Culicines  in  many  towns.  On  the 
strength  of  this  I  have  recently  been  accused  of  proposing  to  rid  the  whole  of 
Freetown  of  malaria  by  the  services  of  one  man  only  ! 


7]  QUININE  37 

Anophelines  and  other  mosquitos  specially  interested  them, 
and  innumerable  papers  and  works  on  the  subject  began  to 
be  poured  out.  The  entomological  results  were  invaluable. 
Whereas  in  1898  only  about  a  hundred  species  of  Culicidae 
were  known,  we  have  now  recognised  about  six  hundred,  which 
have  been  carefully  described  in  valuable  works  by  E.  E.  Austen, 
G.  M.  Giles,  L.  O.  Howard,  R.  Blanchard,  and  especially  in  an 
exhaustive  monograph,  by  F.  V.  Theobald,  and  by  many  others. 
Regarding  the  habits  of  the  insects  my  findings  have  been 
generally  confirmed,  without  very  much  really  new  matter  being 
added.  Some  of  the  observers,  being  new  to  the  subject,  have 
laboriously  recorded  facts  (such  as  the  abundance  of  gnats  near 
their  breeding-places,  or  in  ground-floors  of  houses,  or  in  dark 
corners,  or  on  dark  surfaces,  or  their  transportation  by  carriages, 
and  so  on)  which,  I  think,  were  perfectly  familiar  to  all  who 
have  lived  much  amongst  them.^ 

Returning  to  the  subject  of  prevention,  we  must  now  note 
that  an  important  new  method  was  suggested  by  R.  Koch 
during  his  visit  to  Italy  in  1898 — namely,  prevention  by  treat- 
ment of  cases.  This  was  tried  at  once  by  B.  Gosio  in  Grosseto 
in  Italy  [1900].  Towards  the  autumn  of  1899  Koch  went  with 
R.  Pfeififer  and  H.  Kossel  to  Batavia,  where  he  discovered  his  law 
regarding  the  frequency  of  infection  in  native  children  ;  and  in 
December  proceeded  to  German  New  Guinea,  where  he  success- 
fully used  his  method  of  prevention  at  Stephansort  [1900].  This 
method  is  entirely  different  to  the  ancient  one  of  drainage,  or 
to  my  modification  of  it.  It  aims,  not  at  the  reduction  of  the 
carriers  of  the  parasites  in  a  locality,  but  at  the  reduction  of  the 
parasites  themselves  by  the  general  and  complete  treatment  by 

^  Also  many  habits  have  been  ascribed  to  mosquitos,  which  exist  only  in  the 
imagination  of  the  writers.  Thus  Nuttall  says  [1899]  that  Aaron  suggested  destroying 
mosquitos  by  placing  small  lamps  in  trays  of  petroleum  over  ponds  or  marshes  round 
dwellings.  The  gnats,  attracted  by  the  light,  would  fall  into  the  oil.  In  1900  two 
Italian  writers,  one  of  whom  is  supposed  to  have  led  the  way  regarding  the  mosquito 
malaria  theory,  not  only  approved  this  absurdity,  but  added  the  suggestion  that  the 
lamps  "  be  furnished  with  powerful  (j-?V)  reflectors  turned  away  from  the  house."  I 
have  never  in  my  life  seen  mosquitos  attracted  by  lamps. 


38  HISTORY  [Sect. 

quinine  of  all  infected  persons  in  the  locality.  If  this  is  done, 
he  argued,  the  Anophelines,  however  numerous  they  may  be, 
will  be  innocuous,  as  they  will  find  no  parasites  to  carry.  He 
describes  the  method  ably,  and  says  :  "  After  all  these  experiences 
I  consider  myself  warranted  in  stating  that  we  are  in  a  position, 
by  means  of  the  procedure  which  I  have  described,  to  make 
every  malarious  region,  according  to  circumstances,  wholly  or 
nearly  free  from  malaria."  The  method  is  invaluable,  and  there 
is  no  real  rivalry  between  it  and  my  method. 

Most  admirable,  too,  has  been  the  work  in  Italy,  led  by 
A.  Celli,  himself  one  of  the  most  distinguished  students  of 
malaria.  In  1899  he  published  an  excellent  text-book,  in 
which  he  presented  the  whole  subject  of  prevention  according 
to  the  "  new  researches,"  with  a  history  and  accounts  of  various 
preventive  measures.  This  was  followed  by  innumerable 
researches  and  practical  campaigns  throughout  the  country 
— which  have  made  a  great  reduction  in  the  disease.  All 
methods  have  been  adopted,  but  principally  perhaps  the 
various  quinine  methods.  Italy,  however,  is  a  temperate 
European  country,  with  conditions  very  different  to  those 
which  prevail  in  the  tropics — and  the  malaria  there  is  mostly 
rural. 

Still  another  method  consists  in  the  screening  of  houses 
by  wire-gauze,  a  defence  long  employed  in  America  against 
mosquitos.  It  was  now  used  in  Italy  against  Anophelines  ; 
was  much  encouraged  by  the  experiment  of  L.  Sambon  and 
G.  C.  Low  in  the  Campagna  in  1900 ;  and  has  been  widely 
employed  at  Panama. 

In  1898,  the  Colonial  Office  and  the  Royal  Society  appointed 
a  commission,  consisting  of  C.  W.  Daniels,  J.  W.  W.  Stephens 
and  S.  R.  Christophers,  to  follow  up  my  work.  Daniels  left 
the  commission  in  1899  after  some  good  work  in  British 
Central  Africa ;  but  the  other  observers  were  sent  at  my 
recommendation  to  West  Africa  during  the  same  year. 
There  they  continued  our  researches  of  1899,  but  laid  special 


7]  YELLOW  FEVER  39 

stress  on  segregation  for  Europeans.  They  found  many 
interesting  facts  about  mosquitos,  and  also  developed  very 
fully  the  subject  of  infection  of  native  children,  and  the 
causes  of  local  malaria  in  West  Africa.  In  1901  they  were 
sent  to  India  at  my  suggestion,  and  continued  similar  work 
there.  Their  valuable  observations  are  contained  in  a  series 
of  reports  [1899-1903]. 

Also  following  our  first  expedition  to  Sierra  Leone,  the 
Liverpool  School  of  Tropical  Medicine  sent  out  a  stream  of 
expeditions,  all  of  which  gave  useful  information  about  local 
malaria,  or  started  practical  measures. 

At  the  end  of  1900  a  very  important  event  occurred — 
W.  Read,  J.  Carrol,  J.  W.  Lazear  and  A.  Agramonte  proved 
in  Havana  that  yellow  fever  is  carried  by  Stegotnyia  calopus 
{fasciata)  just  as  malaria  is  carried  by  Anophelines.  They 
proved  this  by  direct  experiment  on  men  ;  but  did  not  succeed 
in  finding  the  yellow  fever  organism  either  in  man  or  in  the 
mosquito.  Early  in  1901  General  Leonard  Wood  instructed 
the  Chief  Sanitary  Officer  of  Havana,  then  Major  M.  C.  Gorgas, 
to  commence  operations  against  these  insects.  In  a  few 
months  the  disease  was  banished  from  Havana. 

It  was  very  disappointing  at  this  time  that  so  little  had 
yet  been  done  in  British  possessions  to  combat  malaria  by 
any  of  the  measures  rendered  possible  by  the  previous  dis- 
coveries. There  was  a  brilliant  exception.  On  my  visit  to 
Sierra  Leone  I  had  met  Dr  H.  Strachan,  the  Principal 
Medical  Officer  of  Lagos,  and  he  took  up  the  matter  with 
great  interest.  Fortunately  the  Governor  of  Lagos,  Sir  William 
MacGregor,  himself  a  medical  man  (like  General  Leonard 
Wood),  immediately  saw  the  value  of  the  new  ideas,  and  began 
to  push  malaria  prevention  in  Southern  Nigeria  in  a  most 
admirable  way  by  all  methods — drainage,  quinine,  wire-gauze 
and  public  instruction.  But  elsewhere  local  bodies  had  ignored 
the  subject  almost  entirely.  Even  in  Sierra  Leone,  where  the 
way  had  been  pointed  out  exactly,  and  where  the  disease  was 


40  HISTORY  [Sect. 

the  principal  enemy  of  the  colony,  little  had  been  done.  The 
Acting  Governor,  now  Sir  Matthew  Nathan,  who  had  been  very 
sympathetic  during  our  visit  in  1899,  had  left  for  the  Gold 
Coast ;  and,  beyond  appointing  a  single  person  for  a  few 
months  to  check  the  mosquitos,  the  municipality  of  Freetown 
had  dropped  the  matter.  Calcutta,  where  also  I  had  suggested 
an  anti-mosquito  campaign  in  1899,  had  done  the  same.  Every- 
where, my  proposal  to  reduce  mosquitos  in  towns  was  treated 
only  with  ridicule. 

Early  in  1901,  therefore,  I  determined  to  try  and  give 
an  object  lesson  in  the  work  recommended  by  me.  A 
rich  gentleman  of  Glasgow  kindly  offered  me  ;^2,0C)0  to 
defray  expenses ;  and  others  helped  me  in  various  ways. 
On  the  2nd  July  I  arrived  with  Dr  M.  Logan  Taylor,  at 
Freetown,  and,  with  the  support  and  approval  of  the  Governor, 
Sir  Charles  King  Harman,  commenced  the  work  at  once. 
Since  1899  I  had  gradually  become  convinced  that  anti- 
mosquito  campaigns  had  better  be  conducted,  not  only  against 
Anophelines,  but  against  all  kinds  of  mosquitos  at  once  ;  and 
this  opinion  was  strongly  reinforced  by  the  yellow  fever  dis- 
covery just  made,  and  also  by  the  fact  that  certain  Culicines 
carry  filaria.  In  fact,  since  then  I  have  always  maintained 
the  opinion  which  may  be  put  as  follows :  //  is  one  of  the  first 
sanitary  duties  of  all  municipalities  and  town  councils  in  warm 
climates  to  keep  down  as  much  as  possible  the  numbers  of 
mosquitos  within  the  area  placed  under  them.  We  therefore 
engaged  the  services  of  twenty  men,  to  whom  the  Governor 
added  twelve ;  and  with  these  we  removed  piles  of  mosquito- 
breeding  rubbish  from  the  back  yards  of  houses,  and  drained, 
emptied,  filled  up  or  oiled  numbers  of  Anopheline  pools.  I 
returned  to  my  duties  in  Liverpool  on  the  i6th  August;  but 
M.  Logan  Taylor  continued  the  work.  In  September  C.  W. 
Daniels  of  the  London  School  of  Tropical  Medicine  arrived 
in  Sierra  Leone,  and  reported  favourably  on  the  work  ;  and 
in  January  1902  I  visited  it  again  for  a  week  to  watch  progress. 


7]  VARIOUS   CAMPAIGNS  41 

There  is  no  doubt  that  a  great  reduction  in  the  number  of 
mosquitos  was  effected  by  our  measures ;  but,  of  course,  our 
work  was  meant  only  for  a  temporary  object  lesson,  and  we 
stated  clearly  that  the  improvement  would  last  only  if  our 
measures  were  continued  by  the  local  authorities.  Later  in 
1902,  however,  Logan  Taylor  reported  that  these  authorities 
did  not  appear  very  anxious  to  continue  them  ;  and  we 
consequently  closed  the  work  when  our  money  was  expended 
— having  done,  we  thought,  as  much  as  private  persons 
could  do.^ 

After  my  third  visit  to  Freetown,  Prince  August  d'Arenberg, 
President  of  the  Suez  Canal  Company,  asked  me  to  advise 
regarding  the  prevention  of  malaria  at  Ismailia  on  the  Canal. 
I  arrived  there  in  September  1902  with  Sir  VV.  Macgregor, 
who  did  me  the  honour  to  accompany  me.  The  town  was 
swarming  with  both  Culicines  and  Anophelines ;  and  efforts 
to  control  the  malaria  by  liberal  quinine  distribution  had  not 
succeeded.  I  advised  a  continuance  of  this  measure  with 
general  mosquito-reduction.  In  this  case  "intelligent  and 
persistent  efforts "  were  made  ;  and  within  a  year  the  insects 
of  both  groups  were  almost  entirely  banished,  and  the  ad- 
missions for  malaria  reduced  from  about  2,000  a  year  to  214. 
Since  then,  endemic  malaria  has  entirely  disappeared.  Dr  A. 
Pressat  says  that  he  originally  reduced  the  disease  by  means 
of  a  mosquito  brigade  of  only  four  men  qui  a  tout  fait  [1904]. 

Scarcely  less  brilliant  was  the  campaign  at  Klang  and 
Fort  Swettenham  in  the  Federated  Malay  States,  commenced 
in  1 90 1,  and  carried  out  chiefly  by  Dr  Malcolm  Watson.  At 
Hong  Kong  also,  a  campaign  was  commenced  at  the  same 
time,  and  carried  out  chiefly  by  Dr  J.  C.  Thomson  with  very 
good  results.  Several  anti-mosquito  campaigns  have  been  con- 
ducted in  the  United  States;  and  in  1906- 1907  my  brother, 
E.  H.  Ross,  acting  under  the  orders  of  Sir  Horace  Pinching, 

1  A  year  later  it  was  pretended  that  our  efforts  had  failed,  and  the  only  thanks 
which  we  ever  received  for  our  pains  was  a  subterranean  effort  to  injure  us. 


42  HISTORY  [Sect. 

completely  cleared  Port  Said  of  Culicines.  Other  campaigns 
have  been  those  of  Dr  A.  Balfour  at  Khartoum,  of  many 
officers  in  Candia,  some  West  Indian  Islands,  the  East  Indies, 
and  Durban.  In  1906  I  went  to  Greece  to  advise  regarding 
malaria  at  Lake  Kopais  ;  and  in  1907  to  Mauritius  (with 
Major  C.  E.  P.  Fowler)  to  advise  the  Government  on  malaria 
prevention  there.  As  regards  magnitude,  however,  the  great 
American  campaign,  under  Colonel  Gorgas,  against  both  malaria 
and  yellow  fever,  at  Panama ;  that  of  Oswaldo  Cruz  at  Rio 
Janeiro  ;  and  that,  so  well  guided  by  Drs  Ed.  and  Et.  Sergent 
in  Algeria,  have  long  held  public  attention.  Descriptions  will 
be  found  under  the  appropriate  sections  in  this  book. 

In  spite  of  these  brilliant  examples,  however,  little  was 
attempted  against  malaria  for  many  years  in  the  vast  bulk  of 
tropical  countries.  It  is  true  that  questions  in  Parliament 
and  elsewhere  often  led  to  assertions  that  much  was  being 
done  ;  but  those  who  really  know  what  might  have  been  done, 
and  who  were  in  a  position  to  obtain  the  information  from  men 
on  the  spot,  remained  far  from  satisfied.  On  23rd  April  1906 
the  Earl  of  Elgin,  Secretary  of  State  for  the  British  Colonies, 
issued  a  circular  at  the  instance  of  Colonel  Seely,  M.P.,  to  all 
Governors  of  Crown  Colonies  asking  for  specific  details  on  this 
point.  In  September  of  the  same  year  I  read  a  paper  at  the 
14th  International  Congress  of  Hygiene  at  Berlin  [1907]  in 
which  I  described  what  had  been  done  in  some  tropical  localities, 
and  also  criticised  the  lack  of  efforts  in  others.  Still,  however, 
little  effect  was  produced,  and  I  came  to  the  conclusion  that  in 
many  malarious  places  the  authorities  had  no  real  desire  to  carry 
out  anti-malaria  measures,  or  else  were  entirely  ignorant  of 
how  to  do  so.  For  example,  though  they  always  urged  lack 
of  funds  as  an  excuse,  they  often  omitted  to  do  things  which 
would  cost  almost  nothing,  such  as  to  undertake  the  measure- 
ment of  malaria,  to  issue  careful  reports,  or  to  form  the  nucleus 
of  an  organisation. 

At  the  end  of  February  I  visited  the  Medical  Congress  at 


8]  REMARKS  43 

Bombay  in  order  to  ascertain  what  work  was  being  done  in 
India,  but  met  only  with  disappointment.  A  few  months 
later,  therefore,  I  gave  a  lecture  at  the  Royal  Institution  of 
Great  Britain,  in  which  I  ventured  to  complain  very  strongly 
regarding  this  state  of  affairs  [1909].  Fortunately  this  has 
been  followed  by  a  considerable  improvement.  An  anti-malaria 
league  was  started  in  South  Africa,  and  the  Indian  Govern- 
ment held  a  conference  on  malaria  at  Simla,  which  practically 
endorsed  all  our  teaching.  Moreover,  other  movements  for  the 
generalisation  of  anti-malaria  measures  are  now  on  foot,  and 
will,  I  hope,  produce  better  results. 

8.  Remarks. — Such  in  brief  is  the  august  history  of  malaria 
— and  some  day  it  will  be  considered  as  being  no  unimportant 
part  of  the  world's  history.  To  the  thoughtful  student  of  human 
affairs  it  contains  many  points  of  interest. 

We  should  note  in  the  first  place  that  several  methods  of 
prevention  were  well  known  long  before  the  mosquito-theorem 
was  established.  Probably  the  ancients,  and  certainly  the 
Italians,  since  the  time  of  Lancisi  (171 7),  were  so  well  acquainted 
with  the  good  effect  of  drainage  that  this  principle  was  accepted 
as  a  dogma  in  all  the  medical  schools.  The  excellent  results 
of  quinine,  both  for  cure  and  prevention,  have  also  been  well 
known,  at  least  since  the  time  of  Maillot  in  Algeria  (1834) — so 
well  known  in  fact  that  the  Government  of  India  has  sold  the 
drug  for  many  years  at  the  public  post-offices  for  a  small  price. 
Even  the  benefit  of  using  a  mosquito-net  during  sleep  was, 
I  remember,  looked  upon  as  an  elementary  doctrine  when  I  first 
went  to  India  in  1881.  The  mosquito-theorem  has  merely 
verified  and  precised  these  old  ideas. 

It  was  therefore  I  think  possible,  long  before  1899,  to  reduce 
the  disease  anywhere  on  a  large  scale.  Efforts  in  this  direction 
would  have  been  invaluable  in  numbers  of  settlements  in 
Africa  and  in  the  East  and  West  Indies  ;  but  were,  I  believe, 
seldom  if  ever  made.     Certainly  many  intelligent  medical  men 


44  HISTORY  [Sect. 

advocated  them  ;  but  there  is  a  wide  interval  between  the 
suggestion  of  public  health  measures  and  their  execution. 
Where  they  were  commenced  they  were  soon  abandoned ;  no 
continuous  public  policy  against  the  disease  seems  ever  to  have 
been  adopted  ;  settlements  were  left  for  years  at  the  mercy  of 
marshes  known  to  be  poisonous  ;  and  the  methodical  distribu- 
tion of  quinine  remained  undreamed  of.  I  have  little  doubt 
that  if  more  intelligence  had  been  shown  in  these  respects 
many  of  these  settlements  would  have  already  grown  into 
prosperous  states. 

Laveran's  discovery  of  1880  was  one  not  only  of  theoretical, 
but  of  practical,  importance.  It  enabled  medical  men  to  dis- 
tinguish with  certainty  cases  of  malarial  fever  from  other  diseases, 
and,  after  making  the  diagnosis,  to  treat  the  patient  methodically. 
But  many  years  elapsed  before  it  began  to  be  used  for  these 
purposes.  The  parasites  were  not  seen  in  India,  for  example, 
until  1887  (by  Vandyke  Carter).  I  did  not  hear  of  the  dis- 
covery until  1888,  and  did  not  see  the  parasites  until  1894. 
Scarcely  half  a  dozen  men  were  studying  them  in  India  at  that 
time.  The  use  of  the  microscope  scarcely  became  general 
anywhere  in  the  tropics  until  after  1900;  and  quite  recently 
medical  men  have  told  me  of  hospitals  which  were  not  even 
provided  with  these  indispensable  instruments.  Numbers  of 
others  had  never  read  the  fundamental  literature  ;  and  up  to 
the  present  day  many  colonies  possess  no  sufficient  organisa- 
tion for  circulating  recent  medical  papers.  Yet  in  most  tropical 
countries  there  were  large  public  medical  services  which  ought 
to  have  been  properly  provided  for  in  these  respects. 

It  is  surprising,  when  we  remember  that  malaria  often 
causes  a  third  of  the  sickness  in  a  place,  to  note  that  Laveran's 
discovery  was  not  immediately  followed  by  public  investigations 
on  the  subject,  especially  as  to  the  route  of  infection.^  The 
work  was  done  almost  entirely  by  private  persons.     Even  when 

^  In  1898  the   Government  of  India  appointed  me   to  undertake  researches  on 
malaria— this  being,  I  believe,  the  first  case  of  the  kind. 


8]  INACTION  45 

information  was  thus  obtained,  it  was  left  for  years  untaught  in 
the  medical  schools,  or  neglected  in  practice.  But  worse  than 
this,  little  has  been  done  even  to  encourage  the  private  workers. 
Indeed  I  know  of  several  cases  where  such  workers  have 
received  for  their  pains  nothing  but  the  ridicule  of  less  laborious 
colleagues,  and  the  persecution  of  jealous  superiors.^ 

There  was  no  reason  why  the  prevention  of  malaria  accord- 
ing to  the  new  methods  should  not  have  been  commenced  after 
1899  in  every  civilised  malarious  country.  Such  countries 
possess  responsible  governments  and  expensive  sanitary  and 
medical  services — in  fact  all  the  machinery  required  for  the 
work.  But  the  efforts  actually  made  have  been  due  almost 
entirely  to  isolated  enthusiasts,  while  in  many  places  nothing 
approaching  a  genuine  campaign  has  even  yet  been  attempted. 
In  others,  again,  some  efforts  have  been  reported,  but  their 
perfunctory  nature  is  only  too  apparent  to  those  who  are 
acquainted  with  the  subject.  Yet  the  work  has  been  done,  and 
well  done,  in  many  places.  Why  then  has  it  not  been  done 
in  all? 

The  facts  are  undeniable.  In  numerous  localities  the  disease 
causes  not  only  an  immense  amount  of  sickness,  but  a  great 
loss  of  efficiency  amongst  officials,  soldiers,  workmen  and  the 
general  public,  and  a  corresponding  waste  of  public  money  and 
reduction  of  prosperity.  It  can  be  combatted  only  by  well- 
organised  government  action ;  and  governments  admit  their 
responsibility  in  such  matters.  Yet  governments  have  taken 
little  part  in  the  investigation  of  malaria,  and  have  even 
neglected  to  utilise  for  practical  purposes  the  investigations  of 
others.  Nor  is  the  case  of  malaria  the  only  one  of  the  kind. 
Filiriasis  is  very  prevalent  in  many  localities,  where  it  produces 
numerous  unpleasant  diseases ;  yet  P.  Manson's  discovery  of 
1877,  that  the  parasite  is  carried  by  mosquitos,  has  scarcely 
ever  been  utilised  up  to  the  present  (except  perhaps  in  the  case 

^  The  treatment  of  my  brothers  in  Egypt  is  well  known.  In  British  administration 
we  do  not  expect  gratitude  for  scientific  work  ;  but  is  there  anything  more  childish 
than  to  punish  such  labours  by  gratuitous  persecution  ? 


46  HISTORY  [Sect. 

of  G.  C.  Low's  work  at  Barbados).  Another  example  (and  I 
could  quote  many)  is  that  of  the  entry  of  plague  into  India  in 
1896 — an  event  which  has  destroyed  millions  of  lives  and 
wasted  millions  of  money.  Precisely  similar  complaints  are 
frequently  heard  regarding  diseases  of  animals  and  of  crops,  and 
regarding  mining,  manufactures  and  commerce. 

The  student  will  do  well  to  ask  himself  the  cause  of  this 
phenomenon — which  is  of  fundamental  importance  in  connection 
with  our  subject.  We  recognise,  of  course,  that  the  world  is  by 
no  means  perfect ;  but  for  this  very  reason  we  should  endeavour 
to  extricate  the  causes  of  its  imperfections.  The  following 
points  may  be  suggested  for  consideration,  or  correction,  by 
the  reader. 

The  principal  cause  of  the  faults  referred  to  seems  to  me  to 
lie  in  a  curious  tone  of  thought  which  is  now  very  prevalent, 
especially  in  this  country ;  according  to  which  all  matters  of 
practical  utility  to  mankind  are  looked  upon  as  being  rather 
base  preoccupations  for  the  more  perfect  type  of  human  being. 
The  study  of  nature,  the  extirpation  of  disease,  the  management 
of  cities,  invention,  the  development  of  agriculture,  manufactures 
and  commerce,  and  the  organisation  of  prosperity  are  inferior 
things.  We  are  to  seek  a  higher  level  in  personal  manners, 
literary  criticism,  eloquence,  sport,  party  politics,  sectarian 
dogma,  and  so  on.  It  is  the  modern  equivalent  of  Indian 
fakirism,  by  which,  lost  in  various  lofty  speculations,  we  are 
tauerht  to  remain  content  in  the  midst  of  starvation  and  disease. 

This  spirit,  fostered  in  us  from  childhood,  leads  to  false 
ideas  of  government.  The  scientific  side  of  administration  is 
apt  to  be  forgotten  in  the  noise  of  endless  and  despicable 
party  strife ;  progress  ceases  while  we  discuss  abstract  notions 
about  law,  liberty,  representation,  nationalism  and  so  forth ; 
the  machine  refuses  to  work  while  the  mechanics  are  quarrelling 
over  the  lubrication.  The  result  is  precisely  what  may  be 
imagined — cities  built  without  sense  or  forethought,  filthy  slums, 
hovels  filled  with  disease,  gulfs  of  destitution  ;  and  the  voices  of 


8]  IRRATIONALISM  47 

those  who  would  better  this  state  of  affairs  by  scientific  methods 
are  lost  among  the  yells  of  the  opposing  factions. 

Though  in  the  tropics  we  are  still  spared  many  of  the  evils 
of  party  government,  the  same  spirit  of  inutilitarianism  often 
remains.  Money  which  would  suffice  for  the  assainment  of 
whole  towns  is  wasted  rather  on  the  construction  of  extrava- 
gant town  halls  and  post-offices.  The  cost  of  a  new  hospital 
would  often  suffice  to  prevent  more  cases  of  sickness  than  are 
treated  in  it ;  and  that  of  invaliding  to  prevent  the  disease 
which  causes  it.  The  British  Government  spends  ;^  15,000,000 
a  year  on  the  education  of  children ;  but  gives,  I  believe, 
literally  nothing  for  the  scientific  investigation  of  scarlet 
fever,  measles,  whooping  -  cough,  chicken  -  pox  and  mumps, 
which  work  such  mischief  among  these  same  children  —  a 
fact  which  by  itself  proves  the  illogical  nature  of  the  educa- 
tion given.  Similarly  in  the  tropics  I  have  seen  a  large 
class  of  coloured  children,  almost  all  of  whom  were  suffer- 
ing at  the  time  from  fever  or  enlargement  of  the  spleen, 
being  taught  the  dates  of  accession  of  the  Plantagent  kings ! 
We  all  know  how  often  sanitation  receives  only  the  crumbs 
which  remain  at  the  bottom  of  the  public  pocket  after  all 
the  other  departments  have  been  well  fed — the  final  triumph 
of  fakirism. 

But  we  must  not  blame  the  general  public  alone.  We  are 
familiar  with  the  manner  in  which  individual  medical  men 
give  their  services,  not  only  to  medical  science,  but  for  the 
gratuitous  treatment  of  the  poor ;  yet  nevertheless  the  medical 
profession  as  a  body  possesses  little  influence  or  power  in 
public  affairs.  It  is  a  body  without  a  head.  It  does  not 
take  a  high  enough  stand  with  the  public  regarding  scientific 
and  sanitary  matters.  The  duty  of  the  profession  does  not 
lie  merely  in  teaching  and  in  the  cure  of  the  sick,  but  in 
everything  that  appertains  to  the  health  of  the  people.  Yet 
it  is  apt  to  be  dominated,  not  by  this  lofty  ambition,  but  by 
other  ideals  ;   and  it  therefore  seldom   bestirs  itself  regarding 


48  HISTORY  [Sect.  8 

its  higher  duties.  Can  we  wonder  then  that  governments  also 
are  apt  to  neglect  the  same  duties  ? 

Several  high  officials  have  told  me  that  medical  men  do 
not  often  become  good  administrators.  This  is  probably  due 
to  the  fact  that  governments  seldom  take  enough  care  in  the 
selection  of  their  administrative  medical  officers.  I  have  seen 
many  able  men  in  such  posts,  but  others  who  were  not  fitted 
for  them.  The  head  of  a  large  sanitary  or  medical  depart- 
ment should  possess  a  full  knowledge  of  the  recent  scientific 
and  practical  advances  in  his  subject.  Too  often  we  find 
officials  who  have  been  promoted  merely  on  account  of 
seniority,  or  in  consequence  of  self-service ;  men  who  express 
contempt  of  these  recent  advances  because  they  know  nothing 
about  them  ;  who  have  no  ideas,  and  who  make  no  efforts. 
Such  men,  when  taxed  with  defects  in  their  department, 
always  complain  that  the  Government  does  not  grant  enough 
funds.  But  they  are  the  responsible  heads  of  those  departments ; 
and  if  their  advice  is  neglected  they  should  resign  their  post. 

In  1730  Dr  Thomas  Fuller  {Exanthematologia,  Charles 
Rivington,  London  —  quoted  by  W.  S.  Thayer)  wrote:  "Can 
any  man,  can  all  the  Men  in  the  World,  tho'  assisted  by 
Anatomy,  Chymistry,  and  the  best  Glasses,  pretend  positively 
and  certainly  to  tell  us,  what  particles,  how  sized,  figured, 
situated,  mixed,  moved,  and  how  many  of  them,  are  requisite 
to  produce  a  quartan  ague,  and  how  they  specifically  differ 
from  those  of  a  tertian  .  .  .  ? "  We  are  now  able  to  tell  all 
these  things.  They  have  been  written  in  hundreds  of  books^ 
and  are  familiar  to  thousands  of  students.  Those  who  belittle 
the  powers  of  science  are  not  always,  perhaps,  the  wisest  of 
men. 

The  history  of  malaria  contains  a  great  lesson  for  humanity 

that  we  should  be  more  scientific  in  our  habits  of  thought, 

and  more  practical  in  our  habits  of  government.  The  neglect 
of  this  lesson  has  already  cost  many  countries  an  immense 
loss  in  life  and  in  prosperity. 


CHAPTER   II 

SUMMARY   OF   FACTS   REGARDING   MALARIA 
{Suitable  for  Public  Instruction) 

9.  The  Parasites  and  the  Fever.  —  Malaria,  or  Malarial 
Fever,  is  also  known  by  the  names  Paludism,  Marsh  Fever, 
Jungle  Fever,  Ague  and  Periodic  Fever.  It  is  often  called 
by  local  names  such  as  Country  Fever,  West  African  Fever, 
Burma  Fever ;  and  varieties  of  it  are  called  Intermittent  Fever 
Remittent  Fever,  Pernicious  Fever  and  Blackwater  Fever, 

Malarial  fever  occurs  more  or  less  in  all  warm  climates, 
especially  in  the  summer,  after  rains,  and  near  marshy  ground  ; 
and  causes  a  quarter  or  more  of  the  total  sickness  in  the  tropics. 

It  is  caused  by  enormous  numbers  of  the  minute  parasites 
of  the  blood  called  Plasmodia. 

These  parasites  are  introduced  into  the  blood  through 
the  proboscis  of  certain  species  of  the  mosquitos  called 
Anophelines. 

On  being  introduced,  each  parasite  enters  one  of  the  red 
corpuscles  of  the  blood,  in  which  it  lives  and  grows. 

On  reaching  maturity  each  parasite  produces  a  number  of 
spores  which  escape  from  the  containing  corpuscle,  and  enter 
fresh  corpuscles ;  and  this  method  of  propagation  may  be 
continued  indefinitely  for  years. 

Thus,  though  only  a  few  hundreds  or  thousands  of  the 
parasites  may  have  been  originally  introduced  through  the 
mosquito's  proboscis,  their  number  rapidly  increases  until  as 
many  as  some  millions  of  millions  of  them  may  exist  in  the 
blood. 

At  first,  while  the  number  of  parasites  is  still  small,  the 

49  D 


^' 


50  SUMMARY    OF    FACTS    REGARDING    MALARIA      [Sect. 

infected  person  may  remain  apparently  well.  When,  however, 
the  number  is  large  enough,  he  begins  to  suffer  from  fever. 

The  parasites  tend  to  produce  their  spores  all  at  the  same 
time ;  and  it  is  at  the  moment  when  these  spores  escape  that 
the  patient's  fever  begins. 

The  fever  is  probably  caused  by  a  little  poison  which 
escapes  from  each  parasite  with  the  spores. 

After  from  six  to  forty  hours  or  more  this  poison  is 
eliminated  from  the  patient's  system  ;  and  his  fever  then  tends 
to  leave  him. 

In  the  meantime,  however,  another  generation  of  parasites 
may  be  approaching  maturity,  and  may  cause  another  attack 
of  fever  like  the  first ;  and  so  on,  indefinitely  for  weeks  or 
months.  In  this  manner  the  attacks  of  fever  follow  each  other 
at  regular  intervals. 

But  it  often  happens  that  before  one  attack  has  entirely 
ceased  another  one  commences ;  so  that  the  attacks  overlap 
each  other,  and  the  fever  is  continued. 

After  a  time,  even  without  treatment,  the  number  of  parasites 
may  decrease,  until  not  enough  of  them  are  left  to  produce 
fever ;  when  the  patient  improves  temporarily. 

It  generally  happens,  however,  sooner  or  later,  that  the 
number  of  parasites  increases  again  ;  when  the  patient  again 
suffers  from  another  series  of  attacks. 

Such  relapses  are  frequently  encouraged  by  fatigue,  heat, 
chill,  wetting,  dissipation  and  attacks  of  other  illness. 

They  may  occur  at  intervals  for  a  long  time  after  the  patient 
was  first  infected,  and  after  he  has  moved  to  localities  where 
there  is  no  malaria. 

It  is  probable  that  as  long  as  one  parasite  remains  alive  in 
the  patient's  blood  he  may  remain  subject  to  such  relapses. 

Besides  fever,  the  parasites  often  produce  anaemia  and 
enlargement  of  the  spleen,  especially  in  patients  who  have 
suffered  from  many  relapses. 

Death  is  sometimes  caused  by  sudden  and  grave  symptoms. 


lo]  THE   PARASITES   AND   THE   FEVER  51 

Chief  among  these  are  the  symptoms  known  as  Blackwater 
Fever,  or  Haemoglobinuria,  which  generally  occurs  in  old  and 
neglected  infections. 

Death  is  also  often  caused  during  the  course  of  a  malarial 
infection  by  other  diseases,  such  as  pneumonia  or  dysentery, 
acting  upon  a  constitution  already  enfeebled  by  the  parasites. 

If  the  patient  survives,  the  parasites  tend  to  die  out  of 
themselves,  without  treatment,  after  a  long  period  of  illness — 
leaving  him  more  or  less  "  immune." 

The  parasites  are  at  leasFof  three  kinds,  which  can  easily 
be  distinguished  in  blood  placed  under  the  microscope.  These 
are  (i)  the  parasite  which  produces  its  spores  every  three  days 
and  causes  quartan  fever ;  (2)  the  parasite  which  produces  its 
spores  every  other  day,  and  causes  tertian  fever ;  (3)  parasites 
which  cause  the  so-called  malignant  fever,  in  which  dangerous 
complications  most  frequently  occur.  -' 

If  a  little  blood  containing  any  one  of  these  species  of 
parasites  is  taken  from  a  patient,  and  is  then  injected  into  a 
vein  of  a  healthy  person,  the  latter  will  almost  certainly  soon 
become  infected  with  the  same  species  of  parasite. 

Closely  similar  parasites  are  found  in  monkeys,  bats,  squirrels 
and  birds. 

As  proved  by  centuries  of  experience,  cinchona  bark,  from 
which  quinine  is  made,  possesses  the  power  of  destroying  the 
parasites  and  curing  the  infection.  But  it  will  not  generally 
destroy  all  the  parasites  in  the  body  unless  it  is  given  in 
sufficient  doses  and  continued  for  several  months ;  and  as 
long  as  a  single  parasite  remains  alive  in  the  blood,  infection 
is  continued  and  the  patient  may  be  subject  to  relapses.  At 
least  five  grains  (1/3  gramme)  of  sulphate  of  quinine  should  be 
taken  by  an  adult  patient  every  day  without  fail  for  four 
months ;  but  he  should  consult  a  medical  man  regarding  de- 
tails of  the  treatment. 

10.    The  Mode  of  Infection Besides  those  forms  of  the 


52  SUMMARY    OF   FACTS   REGARDING   MALARIA     [Sect. 

malaria  parasite  which   produce  spores    in    the   human   body, 
there  are  other  forms,  male  and  female. 

When  certain  species  of  the  mosquitos  called  Anophelines 
happen  to  feed  on  a  patient  whose  blood  contains  the  parasites 
of  malaria,  these  are  drawn  with  the  blood  into  the  insect's 
stomach. 

If  the  sexual  forms  of  the  parasites  are  present  these 
undergo  certain  changes  in  the  mosquito's  stomach ;  the 
females  pass  through  its  wall  ;  and  finally  fix  themselves  to 
its  outer  surface — that  is,  between  the  stomach  and  the  skin 
of  the  insect. 

In   this   position    they   grow    largely    in   size,   and    after   a 
week,    in    favourable    circumstances,    produce     a    number    of. 
spores. 

The  spores  find  their  way  into  the  insect's  salivary  glands. 
This  gland  secretes  the  irritating  fluid  which  the  insect 
injects  through  its  proboscis  under  the  human  skin  when  it 
commences  to  feed  ;  and  the  spores  can  easily  be  found  in 
the  fluid  by  the  microscope. 

Thus  when  a  proper  species  of  Anopheline,  which  has 
more  than  a  week  previously  fed  upon  a  patient  containing 
the  sexual  forms  of  the  parasites  of  malaria,  next  bites  another 
person,  it  injects  the  spores,  together  with  its  saliva,  under 
his  skin — that  is,  generally  into  his  blood. 

These  spores  now  cause,  or  may  cause,  infection  or  re- 
infection in  this  second  person,  as  described  at  the  beginning 
of  this  summary. 

Numerous  birds  and  men  have  been  infected  experimentally 
in  this  manner. 

Thus  the  parasites  of  malaria  pass  alternately  from  men 
to  certain  mosquitos,  and  back  from  these  mosquitos  to  men. 

A  very  large  number  of  parasites  are  known  which  pass 
in  this  manner  from  one  animal  to  a  second  animal  which 
preys  on  the  first ;  and  back  again  from  the  second  animal 
to  the  first. 


lo]  THE   MODE   OF   INFECTION  53 

It  is  not  known  with  certainty  when  and  how  this  process 
first  commenced  ;  but  probably  all  such  parasites  were  origin- 
ally free  living  animals,  which  by  the  gradual  evolution  of 
ages  acquired  the  power  of  living  in  other  animals. 

Thus  also,  it  is  evident  that  malarial  fever  is  an  infectious 
disease  which  is  communicated  from  the  sick  to  the  healthy 
by  the  agency  of  certain  mosquitos. 

From  the  time  of  the  ancients  it  has  been  known  that 
malarial  fever  tends  to  be  most  prevalent  in  the  vicinity 
of  marshes. 

The  parasites  of  malaria  have  never  been  found  in  the 
water  or  air  of  marshes ;  nor  in  decaying  vegetation ;  nor 
in  the  soil.  Attempts  to  produce  infection  by  these  have 
always  failed.  But  the  Anophelines  which  carry  the  parasites 
breed  in  marshes  and  in  marshy  pools  and  streams. 

Rising  from  these  marshes,  they  enter  the  adjacent  houses 
and  feed  on  the  inmates,  mostly  at  night ;  biting  first  one 
person  and  then  others;    and  living  for  weeks  or  months. 

If  an  infected  person  happens  to  be  present  in  any  of 
these  houses,  the  infection  is  likely  to  be  carried  by  the 
Anophelines  from  him  to  the  other  inmates,  and  to  neighbour- 
ing houses. 

Thus  the  whole  neighbourhood  tends  to  become  infected, 
and  the  locality  is  called  "  malarious." 

In  such  localities,  it  is  easy  to  find  the  parasites  of  malaria 
in  the  Anophelines  of  the  proper  species ;  even  in  as  many 
as  25%  or  more  of  them. 

Such  Anophelines  when  taken  from  a  malarious  locality 
to  a  healthy  one  {e.g.,  from  the  Campagna  near  Rome  to 
London)  will  still  infect  healthy  persons  whom  they  have 
been  caused  to  bite. 

So  also,  in  malarious  localities,  the  Anophelines  bite  the 
healthy  new-born  children,  and  infect  many  of  them. 

Such  children,  if  not  thoroughly  treated,  may  remain 
infected  for  years ;  may  become  anaemic  and  possess  enlarged 


54  SUMMARY  OF   FACTS   REGARDING   MALARIA     [Sect. 

spleens ;  and  may  spread  the  infection  to  others.  Later, 
however,  at  the  age  of  twelve  years  or  more,  the  survivors 
tend  to  become  "  immune." 

In  many  malarious  localities  almost  every  child  has  been 
found  to  contain  the  parasites  of  malaria,  or  to  possess  an 
enlarged  spleen. 

In  such  a  locality  therefore,  the  infection  is  constantly 
passed  on  from  the  older  children,  or  from  adults,  to  the 
new-born  infants  ;  so  that  the  locality  may  remain  malarious 
for  years,  or  for  centuries. 

Similarly,  a  new-comer  arriving  in  such  a  locality  is  very 
likely  to  become  infected,  especially  if  he  sleeps  in  an  infected 
house  even  for  one  night. 

A  locality  is  said  to  be  malarious  only  when  healthy  persons 
become  infected  in  it ;  not  when  persons  who  have  become 
infected  elsewhere  happen  to  reside  in  it. 

A  locality  is  malarious  only  when  it  contains  persons  already 
infected  with  the  parasites,  and  also  sufficient  numbers  of  the 
proper  species  or  varieties  of  Anophelines  to  carry  the  infection 
to  healthy  persons. 

The  chances  of  infection  tend  to  be  great  in  localities  where 
there  are  already  numerous  infected  persons,  not  treated  with 
quinine ;  or  where  there  are  numerous  Anophelines  of  the 
proper  species,  not  prevented  from  biting. 

Conversely,  the  chances  of  infection  tend  to  be  less  where 
infected  persons  are  excluded,  or  properly  treated  with  quinine ; 
or  where  the  Anophelines  are  few  in  number,  or  are  prevented 
from  biting. 

11.  Facts  about  Mosquitos.— Gnats,  which  in  the  tropics 
are  commonly  called  mosquitos,  belong  to  the  zoological  family 
of  Insects  known  as  the  Culicidae  (from  the  Latin  culex,  a  gnat). 
They  are  distinguished  from  other  insects  by  a  number  of 
characters ;  and  always  possess  only  one  wing  on  each  side, 
and  a  long  proboscis. 


ii]  MOSQUITOS  55 

Like  that  of  other  insects,  their  life  is  divided  into  four 
stages,  the  egg ;  the  larva  (or  caterpillar)  ;  \hepupa  (or  chrysalis); 
and  the  imago  (or  adult,  winged  insect). 

The  egg  is  laid  on  water  or  near  it,  and  in  warm,  moist 
weather  hatches  out  in  a  day  or  two. 

The  lai^a  is  entirely  aquatic,  and  always  lives  in  water.  It 
swims  and  dives  by  means  of  paddles  and  hairs,  and  feeds  on 
various  aquatic  organisms.  It  cannot,  however,  breathe  under 
water,  but  must  always  rise  to  the  surface  in  order  to  obtain 
air.     After  a  week  or  more  it  becomes  a  pupa. 

The  pupa  still  remains  in  the  water,  generally  floating  on  the 
surface.  After  two  days  or  more  its  skin  cracks,  and  the 
imago  emerges. 

The  imago  remains  standing  for  a  little  while  on  the  empty 
floating  skin  of  the  pupa,  and  then  flies  away. 

Both  males  and  females  are  able  to  suck  fluids  through  the 
proboscis.  As  a  rule  the  male  feeds  only  on  the  juices  of 
plants ;  but  the  female  sucks  the  blood  of  men,  beasts,  birds 
and  reptiles.  The  female  often  returns  to  water  every  few 
days  in  order  to  lay  her  eggs,  of  which  she  may  deposit  several 
hundreds  at  a  time ;  and  then  seeks  another  meal. 

Female  gnats  have  been  kept  alive  in  captivity  for  months. 

In  unsuitable  weather  both  males  and  females  may  take 
refuge  in  damp  places  such  as  cellars,  wells,  out-houses  and 
woods,  where  they  may  remain  for  months  until  better  con- 
ditions prevail. 

As  a  rule  gnats,  like  other  animals,  tend  to  remain  in  the 
locality  where  they  were  born ;  but  a  few  may  occasionally 
stray  to  the  distance  of  half  a  mile  or  more  from  their  breed- 
ing places.  If,  however,  plenty  of  places  where  they  can  obtain 
food  exist  near  at  hand,  there  is  no  reason  why  they  should 
travel  further  for  it.  They  must  also  remain  near  water  to 
drink  and  to  lay  their  eggs  in. 

Gnats  are  generally  favoured  by  warm  weather,  by  plenty 
of  water  suitable  for  their  larvae,  and  by  abundance  of  food. 


56  SUMMARY   OF   FACTS   REGARDING   MALARIA     [Sect. 

They  tend  to  be  diminished  by  various  kinds  of  bats,  birds, 
fish,  insects  and  spiders  which  devour  them  or  their  larvae. 

During  its  life,  a  single  gnat  may  succeed  in  biting  many 
persons  or  animals,  and  in  propagating  diseases  amongst  them. 

The  family  of  Culicidae  or  Gnats  is  divided  into  many  sub- 
families and  genera,  and  contains  some  five  or  six  hundred 
known  species. 

Although  all  these  species  have  many  habits  and  structural 
characters  in  common,  yet  they  all  differ  in  small  details. 
These  have  been  described  at  length  in  a  number  of  special 
books  written  on  the  subject. 

In  the  tropics,  as  a  broad  general  rule,  the  gnats  which 
most  concern  human  beings  belong  to  the  groups  called  Culex, 
Stegomyia  and  Anophelina. 

Culex  pipiens  is  a  very  common  gnat  in  Europe,  and  allied 
species  are  found  almost  everywhere  in  the  tropics.  The  larvae 
occur  principally  in  tubs,  barrels,  cisterns  and  other  vessels 
containing  water,  in  stagnant  ditches,  garden  pits,  holes  in 
rocks  and  trees,  and  so  on.  They  possess  a  long  breathing 
tube  close  to  the  tail  fins ;  and  float  at  the  surface  of  the 
water  with  the  end  of  this  tube  attached  to  the  "  surface 
film,"  and  the  head  hanging  downwards.  When,  disturbed, 
they  wriggle  at  once  to  the  bottom.  The  adult  insects  gener- 
ally present  a  uniform  grey  appearance,  with  pale  yellowish 
bars  across  the  back  of  the  abdomen,  and  plain  unspotted 
wings.  They  bite  almost  entirely  in  the  evening  and  night, 
and  principally  indoors  (in  the  tropics).  The  parasite  which 
causes  elephantiasis,  namely  the  Filaria  bancrofti,  is  carried 
by  them  or  allied  species  in  a  manner  very  similar  to  that 
in  which  the  Anophelines  carry  the  parasites  of  malaria. 

Stegomyia  calopus  and  allied  species  are  very  common  in  the 
tropics,  but  much  less  so  in  temperate  climates.  The  larvae 
breed  in  much  the  same  places  as  those  of  Culex,  but  more 
frequently  in  vessels.  Any  old  biscuit  tin  or  oil  tin,  flower-pot, 
broken  bottle  and  crockery,  tub  or  barrel,  choked   drain,  roof 


ii]  MOSQUITOS  57 

gutter,  etc.,  in  which  rain  or  other  water  has  collected,  is 
almost  sure  to  contain  them,  and  they  frequently  occur  in 
holes  in  trees  and  in  certain  plants.  They  possess  a  short 
stumpy  breathing  tube,  and  float  head  downwards,  like  the 
larvae  of  Culex.  The  adult  insects  are  more  or  less  striped  or 
speckled  black  and  white,  and  have  plain  unspotted  wings. 
They  bite  chiefly  in  the  daytime,  and  often  abound  in  woods 
and  in  the  shade  of  trees.  In  America  Stegomyia  calopus 
carries  yellow  fever. 

The  Anophelines  consist  of  about  one  hundred  and  twenty 
known  species,  some  of  which  carry  malaria  and  are  always 
found  in  malarious  places.  The  larvae  occur  chiefly  in  water 
on  the  ground,  particularly  in  water  which  stands  or  flows 
amongst  grass  or  water  weeds.  Thus  they  abound  in  the  weedy 
margins  of  rivers,  streams,  lakes  and  ponds  ;  in  small  sluggish 
streams  and  streamlets ;  in  water  courses,  drains  and  gutters 
choked  with  weeds ;  in  pools  of  rain  water  lying  on  grass  ; 
in  pits  from  which  earth  has  been  removed,  such  as  the  "  borrow 
pits  "  by  the  side  of  railway  embankments ;  in  cisterns  and  pits 
used  for  watering  gardens ;  in  ornamental  waters ;  in  hollows 
in  rocks  ;  and  in  water  at  the  bottom  of  boats,  etc.  Thus  while 
the  larvae  of  Culex  and  Stegomyia  occur  in  the  small  collec- 
tions of  water  which  abound  in  and  around  houses,  on  the 
other  hand  the  Anophelines  are  principally  -marsh  tnosquitos — 
owing  to  which  malaria  is  generally  more  or  less  connected  with 
marshy  conditions,  and  is  called  Marsh  Fever,  or  Paludism. 
The  larvae  feed  chiefly  on  the  surface  of  the  water — on  which 
they  float  like  sticks,  and  not  with  the  head  hanging  downwards. 
When  disturbed  they  swim  away  backwards  on  the  surface,  and 
sink  to  the  bottom  only  when  much  alarmed.  They  have  no 
breathing  tube,  like  those  of  Culex  and  Stegomyia.  The  adults 
are  speckled  brown  and  white,  or  black  and  white ;  and  gener- 
ally the  wings  are  not  plain,  but  possess  three  or  four  black 
marks  along  or  near  the  front  border.  When  the  insect  is  seated 
at  rest  on  a  wall,  the  tail  projects  outward  at  an  angle  from  the 


58  SUMMARY   OF   FACTS   REGARDING   MALARIA     [Sect. 

wall ;  whereas  the  Culex  and  Stegoniyia  sit  with  the  tail  hang- 
ing downwards,  or  even  nearly  touching  the  wall.  All  these 
facts  enable  any  one  to  distinguish  at  sight  both  the  larvae  and 
the  adults  of  Anophelines  from  those  of  Culex  and  Stegoniyia. 
Anophelines  bite  chiefly  at  night  or  in  the  dusk  —  owing  to 
which  the  malarial  infection  is  generally  acquired  at  night. 
They  enter  houses,  but  also  bite  in  the  open  in  spots  sheltered 
from  wind. 

12.  Personal  Prevention. — If  they  can  avoid  it,  people 
should  not  go  to  live  in  known  malarious  places,  nor  in  the 
vicinity  of  marshes,  nor  close  to  an  infected  native  population. 

Even  in  such,  however,  the  chances  of  infection  can  be  much 
reduced  by  the  careful  use  of  mosquito  nets.  The  net  should 
not  have  the  smallest  hole.  It  should  be  hung  inside  the  poles, 
when  these  are  provided,  and  not  outside  them.  It  should  be 
tucked  under  the  mattress  all  round,  and  should  never  be 
allov/ed  to  hang  down  anywhere  to  the  floor ;  and  it  should  be 
stretched  tight,  in  order  to  allow  every  breeze  to  enter,  and 
should  not  be  hung  in  loose  folds,  which  check  ventilation. 

Those  who  can  afford  it  should  protect  the  windows  of  the 
house  with  wire  gauze,  and  provide  the  doors  with  automatic 
closing  arrangements.  It  is  especially  advisable  to  protect  a 
room,  or  a  part  of  the  veranda,  for  sitting  in  during  the  day 
or  evening. 

Punkas  and  electric  fans,  not  only  drive  away  mosquitos, 
but  also  keep  the  body  cool,  comfortable  and  vigorous,  even  in 
great  tropical  heat. 

Where  there  is  great  danger  of  malaria,  five  grains 
(1/3  gramme)  of  quinine  should  be  taken  regularly  every  day 
just  before  breakfast ;  but  it  is  advisable  to  take  a  double 
dose  at  least  once  a  week — say,  on  every  Sunday. 

In  such  localities,  the  hands  and  feet  may  also  be  protected 
by  gloves  and  boots ;  but  these  cannot  always  be  endured  owing 
to   the   heat  ;    and   it   is  preferable  instead  to  carry  and   use 


12]  PREVENTION  59 

constantly  a  palm-leaf  fan,  with  which  mosquitos  can  be  driven 
off  and  the  body  kept  cool. 

A  small  butterfly-net  of  white  (not  green)  muslin  may  be 
kept  in  the  house  for  the  purpose  of  catching  troublesome 
mosquitos  during  the  day ;  and  the  servants  may  be  taught 
to  use  it  It  may  sometimes  be  easier  to  kill  all  the  mosquitos 
in  a  room  in  this  manner  than  by  fumigation. 

Mosquito  traps  consist  of  boxes  lined  with  black  cloth. 
Attracted  by  this  colour  mosquitos  enter  the  box  for  refuge 
during  the  day.  The  lid  or  shutter  is  then  suddenly  closed  and 
the  insects  within  are  killed  by  a  little  ammonia  or  chloroform 
poured  into  the  box  through  a  protected  opening.  Or,  the  lid 
can  be  made  to  slide  down  to  the  bottom  of  the  box  in  such  a 
manner  as  to  crush  the  inmates. 

To  fumigate  a  room  thoroughly  for  mosquitos  all  the  chinks 
in  the  doors  and  windows  should  be  closed  by  pasting  paper 
over  them.  Then  burn  the  culicide  as  follows  (Sir  Rubert 
Boyce) : — 

1.  Sulphur. — Allow   2   lbs.  of  sulphur  to  1,000  cubic  feet. 

Use   two    pots,   place   them    in    a    pan   containing 
I  inch  of  water  to  prevent  damage,  and  set  fire  to 
the  sulphur  by  means  of  spirit. 
Duration. — Three  hours. 

2.  Pyrethrum.  —  Allow    3    lbs.   to    1,000    cubic    feet,    and 

divide  amongst  two  or  three  pots,  using  the  same 
precautions  as  with  sulphur. 
Duration. — Three  hours. 

3.  Camphor  and  Carbolic  Acid. — Equal  parts  camphor  and 

crystallised  carbolic  acid  are  fused  together  into  a 
liquid  by  gentle  heat.  Vaporise  4  ozs.  of  mixture 
to  each  1,000  cubic  feet ;  this  can  be  done  by  placing 
the  liquid  in  a  wide  shallow  pan  over  a  spirit  or 
petroleum  lamp ;  white  fumes  are  given  off.  To 
avoid  the  mixture  burning,  the  fumes  should  not 
come  in  close  contact  with  the  flame  of  the  lamp. 
Duration. — Two  hours. 


6o  SUMMARY   OF   FACTS   REGARDING   MALARIA     [Sect. 

Remember  that  sulphur  tarnishes  metal  work  and  injures  pianos, 
sewing  machines,  chronometers,  telephones,  etc. 

The  camphor-carbolic  mixture  is  one  of  the  most  agreeable 
and  effective  of  the  various  agents. 

Many  mosquitos  may  be  killed,  without  troubling  to  cover 
the  chinks  with  paper,  simply  by  picking  up  and  destroying 
the  stupefied  insects  near  the  windows  after  the  fumigation. 

The  householder  should  always  take  care  that  no  stagnant 
water  is  allowed  to  remain  anywhere  in  his  premises  in  cisterns, 
drains,  gutters,  tubs,  jugs,  flower-pots,  gourds,  broken  bottles 
and  crockery,  old  tins  and  other  rubbish,  or  in  holes  in  trees, 
or  in  certain  plants  such  as  wild  pineapple  —  in  all  of  which 
mosquitos  are  apt  to  breed.  If  the  water  cannot  be  emptied 
out,  the  larvae  of  the  mosquitos  in  it  may  be  destroyed  by 
pouring  a  little  kerosine  oil,  or  in  the  case  of  drinking  water, 
a  little  eucalyptus  oil,  upon  the  surface.  This  should  be  done 
once  a  week  ;  and  the  householder  should  make  it  a  habit  to 
inspect  his  premises  for  this  purpose  every  Sunday.  Cisterns 
and  tubs  containing  drinking  water  should  be  kept  screened 
in  such  a  manner  as  to  prevent  mosquitos  laying  their  eggs 
on  the  surface  of  the  water.  If  he  follows  this  advice  the  house- 
holder will  generally  obtain  a  great  reduction  in-  the  number 
of  the  insects  in  his  house.  If,  however,  the  plague  continues, 
he  should  appeal  to  the  local  sanitary  authorities. 

It  is  extremely  dangerous  to  sleep  in  a  house  which  is 
occupied,  or  has  recently  been  occupied,  by  infected  persons, 
especially  native  children ;  or  in  or  close  to  an  infected  native 
village. 

13.  Public  Prevention.— As  a  broad  general  rule,  malaria 
causes  a  quarter  or  more  of  the  total  sickness  in  the  tropics. 

Malaria  can  always  be  greatly  reduced,  or  may  even  be 
extirpated,  in  any  locality. 

Large  marshes  in  populous  places  must  be  drained,  deepened 
or  filled  up. 


13]  PREVENTION  6i 

A  proper  permanent  organisation  must  be  established  for 
dealing  with  the  smaller  breeding-places  of  Anophelines,  and 
for  distributing  quinine — especially  to  infected  children.  Other 
measures  may  be  adopted  where  called  for. 

The  cost  is  likely  to  be  more  than  recouped  by  saving 
in  life,  labour,  invaliding,  medical  attendance  and  hospital 
accommodation. 

The  campaign  will  remove  other  mosquito  -  borne  diseases 
as  well  as  malaria ;  and  will  tend  to  improve  general  sanitation 
in  the  locality  where  it  is  undertaken. 


CHAPTER   III 

THE   FUNDAMENTAL   OBSERVATIONS   AND   EXPERIMENTS 

14.  The  Parasites  cause  the  Disease.  —  Having  studied 
the  history  and  a  general  outline  of  our  subject,  we  must 
now  examine  the  fundamental  observations  and  experiments 
in  greater  detail.  It  is  advisable  to  begin  with  the  evidence 
which  proves  that  the  parasites  are  really  the  cause  of  the 
disease, 

(i)  The  parasites  are  not  found  in  those  who  have  not 
suffered  from  malarial  disease.  Laveran  discovered  the  para- 
sites of  malaria  at  Constantine,  Algeria,  in  1880.  Since  then 
the  blood  of  hundreds  of  thousands,  possibly  of  millions,  of 
patients  suffering  from  various  diseases  must  have  been 
examined,  during  the  ordinary  course  of  clinical  work,  in  the 
civilised  countries  of  the  globe.  Yet  I  have  never  heard  of 
a  single  case  in  which  Laveran's  parasites  are  reported  to  have 
been  found  by  a  competent  observer  in  persons  who  have 
never  had  malarial  fever.  For  example,  in  Britain,  which  is 
now  practically  non-malarious,  they  are  never  seen  in  the  vast 
numbers  of  hospital  patients.  In  only  two  cases  that  I  know 
of  have  they  been  observed  in  men  who  have  never  been  out 
of  this  country,  and  both  these  patients  suffered  from  the 
characteristic  symptoms  of  malarial  fever.^  In  the  tropics 
they  are  often  found  in  persons,  especially  children,  who  have 
no  fever  at  the  moment  of  examination ;  but  that  is  another 
matter.  Such  persons  generally  show  other  symptoms  of  the 
disease ;   and   I   know   of  no  case  which  has  been  proved  to 

1  See  the  articles  by  Copeland  and  Smith  [1906]  and  Easton  [1909],  and  page  214. 

62 


Sect.  14]  FUNDAMENTAL   OBSERVATIONS  63 

have  the  parasites  without  having  had  any  symptoms  of  the 
corresponding  malady. 

(2)  The  parasites  can  ahvays  be  found  in  a  large  proportion 
of  malaria  cases.  The  amount  of  blood  examined  under  the 
microscope  is  extremely  small  compared  with  the  total  amount 
of  blood  in  a  patient's  body ;  so  that  if  the  parasites  are  not 
very  numerous  they  may  easily  be  overlooked,  even  by  a 
skilled  observer.  Moreover,  many  cases  come  under  observa- 
tion only  after  the  parasites  have  largely  diminished  in 
numbers  ;  or  do  not  remain  under  observation  long  enough 
for  a  thorough  search  for  the  parasites  to  be  made.  Hence 
we  can  scarcely  expect  to  find  the  organisms  without  fail  in 
every  patient.  But  the  experience  of  thirty  years  proves  that 
the  percentage  of  successes  depends  almost  entirely  on  the 
care  with  which  the  search  is  made. 

Since  Laveran's  discovery  the  parasites  have  been  found 
by  innumerable  observers  in  large  proportions  of  their  cases. 
To  mention  a  few  —  Laveran  himself  observed  them  in  432 
out  of  480  cases  in  Algeria  [1891,  p.  30];  W.  S.  Thayer  and 
J.  Hewetson  in  nearly  all  of  333  hospital  in-patients  in 
Baltimore  [1895] ;  A.  Billet  in  all  of  395  cases  in  Algeria  [1901] ; 
W.  Duggan  in  all  of  400  cases  in  Sierra  Leone  [1897].  In 
Secunderabad,  India,  without  attempting  exhaustive  search,  I 
found  the  parasites  in  69  out  of  112  cases  [1896].  Similar 
figures  are  given  in  most  papers  on  the  subject,  and  the  matter 
has  now  become  a  commonplace  of  clinical  medicine. 

(3)  The  patient' s  fever  begins  at  the  moment  when  the  spores 
of  the  parasites  are  liberated.  This  important  fact  was  discovered 
by  C.  Golgi  at  Pavia,  towards  the  end  of  1885,  and  proves  that 
the  fever  depends  upon  the  parasites.  In  a  masterly  paper 
[1886]  the  author  describes  his  study  of  forty  cases  of  malaria, 
mostly  quartan.  In  twenty-two  of  these  he  followed  the  de- 
velopment of  the  parasites  in  the  peripheral  blood  pari  passu 
with  the  progress  of  the  malady  ;  and  he  gives  five  of  the  cases 
in  detail  as  examples  of  his  finding. 


64  OBSERVATIONS   AND   EXPERIMENTS  [Sect. 

The  first  classical  case  was  that  of  a  woman  suffering  from 
untreated  simple  quartan  fever  (attacks  occurring  every  three 
days).  Her  blood  was  examined  at  11.30  A.M.  on  the 
2nd  November,  at  the  moment  when  her  fever  was  expected 
to  commence,  and  was  found  to  contain  a  few  full  -  grown 
parasites,  and  many  other  ripe  ones  full  of  spores.  The  attack 
commenced  at  noon  while  the  blood  was  being  examined. 
Next  day  there  was  no  fever,  and  the  blood  contained  only 
young  parasites.  The  next  day  (4th  November),  there  was 
still  no  fever,  but  the  young  parasites  had  now  grown  larger 
and  occupied  3/4ths  to  4/5ths  of  the  containing  haematids.  On 
5th  November,  three  hours  before  the  expected  attack,  the 
blood  again  contained  nearly  mature  parasites,  some  with 
commencing  spore  formation.  An  hour  before  the  attack  these 
were  increased  in  number.  The  attack  then  commenced  at 
noon.  Three  hours  later  only  a  very  few  sporulating  forms 
occurred ;  and  five  hours  after  the  attack  all  of  them  had 
disappeared,  being  again  replaced  by  numerous  young  parasites. 
On  6th  and  7th  November  the  same  development  of  the 
parasites  occurred  as  on  the  3rd  and  4th  ;  and  on  8th  November 
there  was  a  third  attack  of  fever  with  parasites  as  on  the 
2nd  and  5th.  Quinine  (i '5  grammes)  was  given  on  the  loth ;  and 
a  fourth  attack  of  fever  occurred  at  5.30  P.M.  on  nth  November. 

The  next  case  described  by  Golgi  was  one  of  "double 
quartan,"  that  is,  two  sets  of  parasites  reaching  maturity  on 
different  days — one  set  giving  severe  attacks  on  24th,  27th  and 
30th  November,  and  the  other  mild  attacks  on  the  23rd,  26th, 
29th  and  so  on.  The  parasites  of  each  set  developed  just  as  in 
the  first  case,  independently  of  those  of  the  other  group.  The 
third  case  was  at  first  triple  quartan  ;  then,  owing  to  the  dying 
out  of  the  different  sets  of  parasites,  double,  and  lastly  single, 
quartan — the  parasites  always  undergoing  the  same  cycle  of 
development.  The  fourth  and  fifth  cases  need  not  be  described 
here. 

These  beautiful  studies  were  quickly  confirmed  by  W.  Osier 


14]  FUNDAMENTAL    OBSERVATIONS  65 

[1886,  1887],  by  many  Italian  workers,  and  by  Mannaberg. 
Such  facts  have  also  now  become  a  commonplace  of  clinical 
medicine. 

(4)  The  different  types  of  malarial  fever  are  caused  by  different 
species  of  parasites.  Since  the  time  of  the  ancients  clinicians 
have  been  acquainted  with  three  different  types  of  fever,  the 
quartan,  the  tertian,  and  the  irregular  or  malignant  type.  This 
variation  of  type  was  equally  surprising  and  inexplicable  until 
Golgi,  after  elucidating  quartan  fever,  commenced  a  study  of 
tertian,  and  showed  that  it  is  produced  by  a  parasite  which 
is  morphologically  different  from  the  quartan  parasite,  and 
reaches  maturity  every  two,  instead  of  every  three,  days.  As 
in  quartan,  however,  the  patient's  fever  begins  at  the  moment 
when  the  spores  are  liberated  [1886,  1889].  Golgi  also  suggested 
that  the  third  variety  of  fever  is  associated  with  a  third  variety 
of  parasite — that  which  produces  the  well-known  "  crescents  "  ; 
and  this  was  proved  to  be  the  case  by  P.  Canalis  [1890]  and 
Marchiafava  and  Celli  [1890],  who  made  a  detailed  study  of  the 
organism.  Numerous  confirmations  followed,  and  the  observa- 
tions are  now  in  general  use  for  clinical  diagnosis. 

(5)  Both  parasites  and  the  fever  may  be  reproduced  in  healthy 
persons  by  the  inocidation  of  infected  blood.  This  has  been  done 
successfully  in  fifty-one  cases,  which  will  be  described  in  the 
following  section, 

(6)  Both  the  parasites  and  the  fever  may  be  reproduced  in 
healthy  persons  by  the  bite  of  infected  mosquitos.  This  has  been 
done  successfully  in  thirty-six  cases,  which  will  be  described  in 
section  17. 

These  facts  are  more  than  suflficient  to  prove  that  the 
parasites  cause  the  disease.  Additional  but  less  precise 
arguments  are : — 

(7)  The  severity  of  the  illness  depends  roughly  on  the  number 
of  parasites  present.  First  suggested  by  Laveran  and  Golgi 
[1886],  this  theorem  is  now  generally  accepted,  but  rather  on 
the  grounds  of  common  experience  than  on  precise  estimations. 

E 


66  OBSERVATIONS   AND   EXPERIMENTS  [Sect. 

(8)  Quinine  reduces  both  the  parasites  and  the  fever.  This 
theorem,  first  suggested  by  Laveran,  is  now  accepted  every- 
where, but  still  requires  more  precise  study. 

(9)  Certain  secondary  symptoms  are  caused  by  the  accumulation 
of  the  parasites  in  certain  organs.  As  frequently  proved  in  the 
case  of  the  malignant  parasites. 

(10)  Both  the  parasites  and  the  fever  tend  to  disapt>ear  in  a 
locality  if  the  carryitig  A  nophelines  are  greatly  reduced  in  number. 
As  shown  in  many  places,  notably  Ismailia. 

15.  Experimental  Blood  Inoculations.  —  These  classical 
experiments,  commenced  independently  of  Laveran's  discovery, 
and  giving  independent  proof  of  a  contagium  vivum  in  malaria, 
are  of  fundamental  importance. 

The  first  experiments  were  those  of  A.  Dochmann  [1880]. 
One  drop  of  the  contents  of  vesicles  of  Herpes  labialis  of  a  boy 
suffering  from  quartan  was  inoculated  subcutaneously  into  a 
healthy  man  on  8th  February  (?)  1880.  The  man  had  rigors 
and  fever  the  same  evening  and  on  nth  February,  and  malaise 
on  14th  February,  no  symptoms  occurring  in  the  intervals. 
Subsequently  three  men  were  similarly  inoculated  with  herpetic 
serum  from  a  girl  with  quotidian.  This  was  followed  by  five 
days'  quotidian  in  one  of  the  men,  and  none  in  the  others. 
Lastly,  a  girl  was  similarly  inoculated  on  12th  April,  and  had 
fever  on  14th  and  i6th  April.  There  appears  to  have  been 
no  incubation  period,  and  I  agree  with  Laveran  that  the  cases 
must  be  rejected.  The  admissible  cases  are  now  given  and 
numbered  for  reference. 

Case  I.  Gerhardt  [1884]. — Source,  quotidian  fever;  i  c.cm. 
of  blood  taken  at  end  of  rigor  and  injected  subcutaneously  into 
B.  S.  on  nth  August  1882.  Subject  had  slight  fluctuations  of 
temperature  22nd  to  26th  August,  and  severe  rigor  and  fever  on 
27th,  28th,  29th  August.  Quinine  2  grams  on  29th  ;  recovery 
after  two  days. 

Case  2.     Ibid. — Source,  quotidian  fever ;  blood  (?  quantity) 


15]  BLOOD    INOCULATIONS  67 

taken  during  attack,  and  inoculated  into  K.  G.  at  2.15  P.M.  on 
4th  July  1883.  Subject  attacked  at  6  P.M.  on  loth  July,  and 
again  at  about  3  P.M.  on  nth,  13th,  17th,  23rd,  25th,  28th,  29th, 
30th  (severe),  31st  July.  Quinine  2  grams  daily,  ist  to  6th 
August.     Recovery  followed. 

Note. — The  author  appears  not  to  have  heard  of  Laveran's 
discovery  ;  but  his  work  was  careful  and  good. 

Case  3.  Marchiafava  and  Celli  [1885]. — Healthy  subject 
was  inoculated  subcutaneously  with  0*5  c.cm.  of  blood  taken 
from  quotidian  cases  during  attack  on  i8th  July  and 
15th  August  (?)  1884.  Again,  intravenously  with  0*5  c.cm. 
taken  from  a  quotidian  case  during  rigor  on  21st  August. 
Again,  intravenously,  with  i  c.cm.  taken  from  a  case  of  double 
tertian  (?  malignant)  six  hours  before  attack,  on  26th  August. 
Subject  had  strong  rigor  one  hour  after  this  last  injection,  and 
further  attacks  on  27th,  30th  August,  and  ist,  3rd  September, 
when  quinine  was  given.  Isolated  attacks  occurred  up  to 
October. 

Case  4.  Ibid. — Subject,  who  had  previously  had  malaria  and 
was  said  to  have  been  cured,  was  inoculated  intravenously  with 
06  to  3'0  c.cm.  of  blood  from  various  cases  on  31st  August,  4th 
and  6th  September.  Left  hospital.  Returned  to  hospital  with 
fever  on  loth  September.  Daily  attacks  like  those  of  the  source 
of  blood  inoculated  on  6th  September,  the  period  of  incubation 
being  said  to  be  seven  days. 

Case  5.  Ibid. — Healthy  subject  inoculated  with  I'O  c.cm.  of 
blood  from  three  cases,  subcutaneously  or  intravenously  on  6th, 
9th  and  13th  September.  Strong  rigor  on  20th  September,  and 
fever  till  25th. 

Note.  —  Confused  experiments.  Type  of  parasites  not 
clearly  seen  (before  Giolgi's  work).  Mariotti 
and  Ciarrochi,  in  whose  clinics  the  work  was 
done,  also  reported  it. 


68  OBSERVATIONS   AND   EXPERIMENTS  [Sect. 

Case  6.  Gualdi  and  AntoHsei  [1889,  No.  225].  Source 
reputed  to  be  quartan  ;  3  c.cm.  injected  intravenously.  Subject 
attacked  ten  days  later  with  malignant  parasites. 

Case  7.  /did. — Same  source,  dose  and  injection.  Another 
subject.  Attacked  twelve  days  later,  also  with  the  malignant 
parasites. 

JVote. — In  these  two  cases  the  quartan  of  the  source  seemed 
to  have  produced  malignant  in  the  subjects ;  but 
the  authors  stated  later  [1889,  No.  264]  that 
the  source  was  subsequently  found  to  contain 
malignant  as  well  as  quartan  parasites,  the  former 
also  being  observed  microscopically — so  that  the 
result  of  the  experiments  was  not  surprising. 

Case  8.  Antolisei  and  Angelini  [1889,  Nos.  226,  227]. — 
Source,  mild  tertian  ;  blood  (?  quantity)  taken  at  beginning  of 
fever ;  injection  intravenous.  Subject  attacked  with  fever  after 
eleven  days  ;  mild  tertian  parasites. 

Case  9.  ll>td. — Same  source  as  previous  case  ;  i  5  c.cm.  of 
blood  taken  at  the  same  time  ;  injection  intravenous.  Subject 
attacked  almost  at  same  hour  as  previous  case.  The  same 
parasites. 

Case  10.  Gualdi  and  Antolisei  [1889,  No.  264]. — Source, 
quartan ;  3  c.cm.  of  blood  injected  intravenously.  Subject 
attacked  after  twelve  days;  quartan  parasites. 

Case  II.  /did  [1889,  No.  274]. — Source,  malignant  parasites 
with  apyrexia  and  (?)  crescents  only  ;  2  c.cm.  of  blood,  intra- 
venous. Subject  attacked  with  irregular  fever  on  ninth  day, 
and  asexual  malignant  parasites  on  tenth  day.  Crescents  on 
eighteenth  day. 

Case  12.  Di  Mattel  [1891,  No.  121].  Source,  malignant; 
(?)  quantity  of  blood  injected  intravenously.  Subject,  a  case  of 
quartan  which  had  (?)  recovered    spontaneously.     A  few  days 


15]  BLOOD    INOCULATIONS  69 

later  small  unpigmented  asexual  forms,  and  crescents  twenty- 
five  days  after  inoculation. 

Case  13.  Ibid. — Source,  quartan ;  (?)  quantity  of  blood, 
intravenous.  Subject,  a  case  containing  crescents  only.  Subject 
attacked  after  fifteen  days  with  quartan  parasites,  the  crescents 
diminishing  in  number. 

Note. — These  two  cases  show  that  a  second  species  of 
parasite  can  be  added  to  a  previous  invasion. 
The  disappearance  of  the  crescents  in  Case  13 
need  not  have  been  due  to  the  new  invasion. 

Case  14.  Calandruccio  [?  1891]. — Source,  quartan  ;  i  c.cm. 
of  blood,  subcutaneously  injected  on  ist  December  1890. 
Subject,  the  author  himself,  attacked  with  quartan  on  iSth 
December ;  relapses  after  two  and  three  months. 

Case  1 5.  Ibid. — Source,  a  case  showing  (?)  only  crescents  ; 
r5  c.cm.  subcutaneous.  Subject,  the  author  after  recovery  from 
previous  infection.  After  fifteen  days  was  attacked  by  severe 
rigor  and  fever,  and  then  crescents  after  three  days.  No  young 
asexual  forms  found.     Several  relapses. 

Case  16.  Ibid. — Source,  quartan  ;  i  c.cm.  of  blood  (?)  sub- 
cutaneous.    Subject  attacked  after  twelve  days  with  quartan. 

Case  17.  Ibid. — Source  containing  only  crescents  ;  i"5  c.cm. 
(?)  subcutaneous.  Subject  the  same  as  in  previous  case,  four 
months  later.  Crescents  found  in  spleen  on  eighteenth  day, 
and  in  peripheral  blood  on  twentieth  day.     No  asexual  forms. 

Note. — Author  seems  to  have  believed  with  Grassi  and 
Feletti  that  the  crescents  were  a  species  by  them- 
selves {Laverania). 

Case  18.  Bein  [1891]. — Source,  mild  tertian.  Blood  drawn 
by  leeches,  taken  out  by  a  syringe,  and  injected  to  the  amount 
of  2  c.cm.  in  this  and  the  three  following  cases.  Subject 
attacked  on  twelfth  day  with  mild  tertian  parasites. 


70  OBSERVATIONS   AND   EXPERIMENTS  [Sect. 

Case  19.  Ibid —  Source,  mild  tertian.  Same  procedure. 
Subject  attacked  on  twelfth  day  with  mild  tertian  parasites. 

Case  20.  Ibid.  —  Source,  mild  tertian.  Same  procedure. 
Subject  attacked  on  tenth  day  with  mild  tertian  parasites. 

Case  21.  Ibid. — Source  same  as  in  last  case.  Same  pro- 
cedure. Subject  attacked  on  tenth  day  with  mild  tertian 
parasites. 

Note. — Four  attempts  failed.  The  injection  was  intra- 
venous in  one  case,  subcutaneous  in  the  others. 
The  type  of  fevej-  was  not  always  the  same  as 
that  of  the  source,  being  sometimes  simple  and 
sometimes  double  tertian ;  but  this  is  easily 
explicable.  The  same  parasite  was  always 
found  in  the  subject. 

Case  22.  Baccelli  [1892]. — Source,  tertian  ;  3  c.cm.  of  blood 
injected  intravenously.  Subject  attacked  with  double  tertian 
parasites  after  six  days. 

Case  23.  Ibid. — Source,  quartan  ;  4  c.cm.  of  blood  contain- 
ing few  parasites,  intravenous.  Subject  attacked  with  single 
quartan  after  eleven  days. 

Case  24.  Sacharofif  [1894].  —  Source,  malignant.  Blood 
drawn  by  leeches,  which  were  kept  on  ice  for  four  days  ;  1/4  c.cm. 
of  this  blood  injected  subcutaneously  on  4th  October  (?)  1893. 
Subject,  the  author  himself,  had  rigor  and  fever  on  i6th  and 
17th.     Malignant  parasites  found  on  latter  date. 

Note. — This  experiment  was  made  during  the  course  of 
study  of  the  vitality  of  the  parasites  in  leeches 
kept  at  freezing  point.  A  second  experiment, 
with  blood  kept  thus  for  seven  days,  failed. 

Case  25.  Bignami  and  Bastianelli  [1894.] — Source,  malig- 
nant ;  2  c.cm.  taken  at  close  of  paroxysm  ;  numerous  parasites. 
Subject  attacked  after  (?)  three  days  with  the  same  parasites. 


15]  BLOOD    INOCULATIONS  71 

Case  26.  Ibid. — Source,  malignant;  5  c.cm.  of  blood  with 
moderate  number  of  parasites,  at  close  of  paroxysm.  Subject 
attacked  after  (?)  four  days  with  the  same  parasites. 

Case  27.  Ibid. — Source,  malignant ;  3/4ths  c.cm.  of  blood 
with  moderate  number  of  parasites  (  ?  scanty).  Subject  attacked 
after  five  days  with  the  same  parasites. 

Case  28.  Ibid. — Source,  malignant;  i/Sth  c.cm.  with  (?) 
numerous  parasites.  Subject  attacked  after  four  days  with  same 
parasites. 

Case  2<^.  Di  Mattei  [1895]. — Source,  quartan;  2  c.cm.  sub- 
cutaneous, on  14th  August  (?)  1894.  Subject  attacked  with 
simple  quartan  on  ist  September  (sixteen  days). 

Case  30.  Ibid. — Same  source  and  same  injection  on  same 
date.  Subject  attacked  with  simple  quartan  on  25th  August 
(eleven  days). 

Note. — Two  other  cases,  injected  subcutaneously  with  0*5 
and  I'O  c.cm.  failed. 

Case  T^i.  Ibid. — Source,  malignant;  2  c.cm.  of  blood  from 
epistaxis  injected  subcutaneously  in  two  places  on  i8th 
September.  Subject  attacked  with  malignant  parasites  on 
3rd  October.  Fever  on  3rd,  4th,  5th,  9th,  loth  October. 
Crescents  on  nth;  quinine  on  i6th.  Fever  again  on  17th; 
quinine ;  recovery. 

Note. —  In  this  paper  author  re-describes  his  earlier  experi- 
ments [1891],  and  also  describes  eight  negative 
attempts  to  transfer  the  malaria  of  birds  from 
bird  to  bird  or  bird  to  man,  and  four  negative 
attempts  to  infect  birds  from  men. 

Case  "^^2.  Bignami  [1898]. — Source,  malignant;  less  than 
one  drop  of  blood,  subcutaneous.  Subject  attacked  after  six 
days  with  the  same  parasites. 

Case  33.  Ibid. — Similar  to  the  above.  Subject  attacked 
after  ten  days  with  the  same  parasites. 


72  OBSERVATIONS   AND   EXPERIMENTS  [SECT. 

Case  7,4.  Mannaberg  [1905]. — Source,  benign  tertian;  0'2 
c.cm.  of  centrifugated  blood  taken  during  paroxysm  ;  sediment 
injected  subcutaneously.  Subject  attacked  after  twenty-one 
days  with  the  same  parasites. 

Case  T,^.  —  Celli  and  Santori  [1897].  Source,  quartan; 
4  c.cm.,  subcutaneous.  The  same  parasites  in  subject  after 
twenty-five  days. 

Case  36.  Idz'd. — Source,  quartan  ;  4  c.cm.,  subcutaneous.  The 
same  parasities  after  twenty-five  days. 

Case  37.  /(^/^. — Source,  quartan ;  4  c.cm.,  subcutaneous. 
The  same  parasites  after  twenty-five  days. 

Case  38.  Id/d. — Source,  malignant ;  i'5  c.cm.,  subcutaneous. 
The  same  parasites  after  thirty  days. 

Case  ^g.  Ibid. — Source,  malignant ;  r5  c.cm.,  subcutaneous. 
The  same  parasites  after  six  days. 

Case  \o.  Ibid. — Source,  malignant ;  r5  c.cm.,  subcutaneous. 
The  same  parasites  after  seventeen  days. 

Note. — In  all  these  six  last  cases  the  blood  was  mixed 
with  sera  of  horse,  buffalo  or  cattle  before  being 
injected,  in  the  hope  of  immunising  the  subject. 

Case  Of! . — Elting  [1899].  Source,  benign  tertian;  3  c.cm, 
of  blood  containing  half-grown  parasites  injected  intravenously 
on  7th  August  (?)  1898  at  (?)  Baltimore.  Subject  had  a  slight 
rise  of  temperature  next  day  and  sharp  rise  to  39*9°  C.  on  loth. 
Benign  tertian  parasites  next  day. 

Case  42.  Ibid. — Same  source  ;  2  c.cm.  taken  and  injected 
'he  same  day.  Fever  on  fifth  day  ;  benign  tertian  parasites  on 
the  previous  day.' 

Case  43.  Ibid. — Source,  malignant,  with  numerous  asexual 
forms  and  a  few  sexual  ones.     Blood  injected  (?)  1-5.  to  4-0  c.cm. 


15]  BLOOD    INOCULATIONS  73 

(?)  intravenously  on  28th  August  (?)  1898.     Fever  night  of  30th 
to  31st ;  malignant  parasites  on  31st;  crescents  on  6th  September. 

Case  44.  Ibid. — Same  source,  method  and  date.  Asexual 
malignant  parasites  found  in  subject  ist  September  with 
commencing  fever.     High  fever  on  3rd,  and  crescents  on  8th. 

Case  45.  Ibid. — Same  source  and  method.  Inoculation  of 
subject  29th  August,  followed  by  a  short  rise  of  temperature  in 
ten  hours,  after  which  there  was  no  fever  till  5th  September. 
Asexual  malignant  parasites  on  previous  day  (4th),  and  crescents 
on  nth. 

Case  46.  Ibid. — Source,  malignant — Case  43  above.  Blood 
(?)  quantity  taken  a  few  days  after  appearance  of  asexual  forms, 
and  (?  how)  injected  on  1st  September.  Asexual  malignant 
parasites  found  on  third  day  after  injection,  and  thirty-two  hours 
before  first  rise  of  temperature.     Crescents  on  ninth  day. 

Case  47.  Ibid. — Same  source,  method  and  date.  Fever  on 
4th  September,  and  asexual  malignant  parasites  on  same  day. 
Crescents  on  1 1  th. 

Case  48.  Ibid.  —  Source,  malignant  —  Case  46.  Blood 
contained  numerous  asexual  forms,  and  1*5  c.cm.  injected 
intravenously  on  9th  September.  Asexual  malignant  parasites 
on  13th,  fever  on  14th,  crescents  on  20th. 

Case  49.  Ibid. — Two  sources — malignant  and  benign  tertian. 
Two  or  three  drops  of  blood  containing  only  malignant  parasites 
injected  subcutaneously  (?)  date.  Next  day  4  c.cm.  from  benign 
tertian  case  injected  intravenously.  Short  rise  of  temperature 
two  hours  after  second  injection  ;  then  normal  for  five  days. 
Fever  seventh  day  after  first  injection,  and  malignant  parasites 
next  day.  Benign  tertian  parasites  ten  days  after  second 
injection ;  both  flourished  together.  Crescents  seventeen  days 
after  first  injection. 

Case  50.     Ibid. — Two  sources — benign  tertian  and  malignant 


74  OBSERVATIONS  AND   EXPERIMENTS  [Sect. 

later.  Blood  from  former,  4  c.cm.  containing  numerous 
parasites,  injected  subcutaneously.  Slight  rise  of  temperature 
six  hours  later.  Marked  fever  on  seventh  day,  and  benign 
tertian  parasites  on  tenth  day. 

On  the  third  day  after  first  rise  of  temperature  (  ?  ten 
days  after  first  inoculation)  the  subject  was  inoculated  with 
(  ?  quantity  of)  blood  containing  numerous  asexual  malignant 
parasites  —  intravenously.  These  were  recovered  in  blood  of 
subject  four  days  later,  together  with  numerous  tertian  parasites. 
Fever  suddenly  ceased  eighteen  days  after  first  injection  ;  then 
seven  days  apyrexia  with  only  one  or  two  tertian  parasites 
each  day.  But  twenty-six  days  after  first  injection,  quotidian 
fever  with  both  parasites  began.     Quinine  and  cure. 

Case  51,  Rosenau,  Parker,  Francis  and  Beyer  [1904]. — At 
Vera  Cruz.  Source,  double  benign  tertian  ("  heavy  "  infection)  ; 
2  c.cm  of  blood  during  rigor,  mixed  with  equal  part  of  salt 
solution,  injected  intravenously  into  subject  at  2  p.m.  on  6th 
November  1903.  Slight  reaction  within  an  hour.  Typical  fever 
and  parasites  at  7  a.m.  on  loth  November,  double  infection 
(section   19  (4)). 

This  closes  the  list  of  positive  experiments,  but  four 
important  negative  ones  with  blood  containing  (?")  only  sexual 
parasites  remain  to  be  recorded. 

Negative  Case  i.  Thayer  [1898,  p.  75]. — Source,  a  patient, 
convalescent  from  first  attack,  had  had  quinine  for  four  days, 
during  which  none  but  crescentic  and  ovoid  forms  were  found 
in  the  peripheral  circulation.  A  hypodermic  syringe  full  of 
his  blood  was  injected  into  median  basilic  vein  of  subject  in 
August  (?  year).  The  latter  was  carefully  observed  for  five 
weeks,  but  never  showed  fever  or  parasites. 

Negative  Case  2.  Elting  [1899]. — Source,  malignant,  with 
crescents  and  asexual  forms,  treated  for  eight  days  with  four 
hourly  doses  of  5  grains  (o'325  grams)  of  quinine,  until  only 
the  crescents  were  left.     Subject,  injected  intravenously   with 


15]  BLOOD    INOCULATIONS  75 

3   to  3*5    c.cm.  of  blood  on  (?)  date,    never   showed  fever    or 
parasites. 

Negative  Case  3.     Ibid. — Same  source,  injection  and  date. 
Subject  showed  neither  fever  nor  parasites. 

Negative  Case  4.     Ibid. — Same  source,  injection  and  date. 
Subject  had  slight  transient  rises  of  temperature  two  and  six 
days  after  inoculation.     No  characteristic  fever  or  parasites. 
Note. — These  four  cases  give  strong  reason  for  supposing 
that    the    sexual   forms   (crescents)   are   not    in 
any  way  concerned   in  the  reproduction  of  the 
parasites  in  the  blood  of  the  patient  who  contains 
them  (section  20  (4)  ). 
I  am  much  indebted  to  Professor  A.  Celli  for  obtaining  for  me 
from  Professor  Giulio  Galli  an  account  of  two  interesting  experi- 
ments performed  by  the  latter,  showing  that  malarial  blood  may 
be  inoculated  without  result  into  subjects  who  are  taking  quinine. 

Negative  Case  5.  G.  Galli  [  ?  ]. — Source,  benign  tertian, 
many  parasites ;  0'5  c.cm.  of  blood  was  injected  subcutaneously 
into  subject,  a  healthy  woman  who  had  been  given  0'4  grams 
of  "state"  quinine  daily  for  five  days.  The  same  dose  was 
continued  on  ist,  2nd,  5th,  6th,  /th,  12th,  13th,  14th  day  after 
inoculation,  and  then  stopped.  Subject  remained  in  hospital 
for  forty-two  days  after  inoculations,  but  showed  no  sign  of 
malarial  infection. 

Negative  Case  6.  Ibid. — Same  source,  amount  of  blood  and 
method  of  inoculation.  Subject,  a  healthy  woman,  was  given 
o"4  grams  of  quinine  daily  two  days  before  inoculation,  and  six 
days  after.  She  remained  in  hospital  thirty-two  days  after 
inoculation,  but  showed  no  sign  of  malarial  infection.^ 

Remarks. — I  have  verified  most  of  these  cases  from  the 
original  literature ;  but  for  a  few  of  them  the  literature  has 
not  been  obtainable.  I  have  also  omitted  a  few  cases  regard- 
ing which  I  can  obtain  no  references. 

^  See  also  section  65  (5). 


76  OBSERVATIONS   AND   EXPERIMENTS  [Sect. 

16.    The    Parasites   develop    in    Certain   Mosquitos.  —  I 

commenced  the  study  of  the  mosquito-theory  of  malaria  in 
Secunderabad,  India,  in  April  1895.  Numbers  of  mosquitos 
of  the  genera  Odex  and  Stegomyia  were  allowed  to  feed  on 
patients  whose  blood  contained  the  sexual  forms  of  the 
parasites,  and  were  afterwards  dissected  in  the  hope  of  finding 
in  them  some  developmental  stage  of  the  organisms.  This 
investigation  was  continued  without  success  until  August  1897. 
Many  hundreds  of  insects  of  various  species  (undetermined)  of 
these  genera  were  thoroughly  searched,  and  many  hundreds 
more  were  examined  less  completely  —  strong  evidence  in 
favour  of  the  view  that  the  parasites  do  not  develop  in  these 
kinds  of  gnats. 

On  the  20th  and  21st  August  1897,  I  found  the  zygotes  of 
the  malignant  parasite  in  two  Anophelines  (species  undeter- 
mined) bred  from  the  larvae  and  fed  on  a  case  of  crescents. 
In  September,  I  found  them  again  under  the  same  conditions 
in  a  mosquito  of  another  species  of  Anopheline  [December  1897 
and  February  1898.] 

About  the  same  time  MacCallum  and  Opie  demonstrated 
the  sexual  nature  of  the  crescents  [1897]. 

On  the  20th  March  1898  I  found  the  zygotes' of  one  of 
the  malaria  parasites  of  birds,  P.  danilevskyz  Grassi  and  Feletti 
1 890  {Proteosovia  Labbe),  in  Culex  fatigans,  and  worked  out 
the  life-cycle  of  these  parasites  in  the  insects  [1898].  It  was 
however  of  fundamental  importance  to  prove  that  the  bodies 
found  in  the  mosquitos  were  really  descended  from  the 
parasites  found  in  the  birds ;  and  the  following  proofs  were 
obtained  : — 

(i)  The  bodies  in  the  mosquitos  contained  the  characteristic 
plasmodin  (pigment)  of  the  parasites  in  the  birds. 

(2)  Their  growth  and  development  were  observed  in  detail 

in  the  insects. 

(3)  Out  of  249  mosquitos  fed  on  birds  with  no  parasites 

or  other  parasites,  not  one  was  found  to  contain  the 


17]  THE    MOSQUITO    CYCLE  77 

bodies  referred  to  ;  but,  out  of  245  mosquitos  fed  on 
birds  showing  P.  danilevskyi,  178  or  72%  contained 
them. 

(4)  Out    of     10     mosquitos    fed    on    a    sparrow    without 

parasites,  none  contained  the  zygotes.  In  10 
mosquitos,  fed  at  the  same  time  on  a  sparrow  with 
moderate  parasites  (i/iooo^  haematids),  292  zygotes 
were  counted.  In  10  mosquitos  fed  at  the  same 
time  in  a  sparrow  with  many  parasites  (1/50 
haematids)   1,009  zygotes  were  counted. 

(5)  In  July  to  August   I   succeeded  in  infecting  22  out  of 

28  healthy  sparrows,  and  some  other  birds,  by  the 
bites  of  infected  mosquitos  [1898,  1905]. 

This  work  was  speedily  confirmed  by  R.  Koch  [1899],  by 
C.  W.  Daniels  [1899],  and,  subsequently,  by  many  others. 

I  completed  my  work  on  human  malaria  in  1899  in  Sierra 
Leone  [1899,  1900] ;  but  in  the  meantime  Bignami,  Bastianelli 
and  Grassi  had  already  observed  that  the  human  parasites  have 
the  same  life-history  [1898- 1899.]  Since  then  the  life-cycle  of 
the  parasites  in  mosquitos  has  been  studied  by  many  workers 
(section  6). 

17.  Experimental  Mosquito  Inoculations.  —  We  should 
begin  by  referring  briefly  to  the  early  studies  which  showed 
that  malaria  cannot  be  communicated  by  marsh  water.  After 
the  efforts  of  Salisbury  in  1866,  Balestra  in  1869,  Safford  and 
Bartlett,  Archer,  Bargellini,  Klebs  and  Tommasi  -  Crudeli  — 
well  summarised  in  the  paper  of  the  last  named  [1879] — to 
incriminate  various  organisms  as  the  cause  of  the  disease, 
several  Italians  carried  out  good  researches  on  the  effect  of 
drinking  water.  Celli  failed  in  infecting  six  people  by  water 
brought  from  the  Pontine  Marshes  [1886] ;  and  Brancaleone 
and  Marino  performed  similar  experiments.  The  work  of 
Agenore  Zeri  [1890]  was  very  complete.     He  gave  water  from 

^  Very  roughly  computed. 


78  OBSERVATIONS   AND   EXPERIMENTS  [Sect. 

the  Pontine  marshes  and  elsewhere  to  nine  persons  to  drink 
in  doses  between  3  and  i"5  litres  a  day  for  five  to  twenty  days 
each.  To  sixteen  others  he  administered  the  water  in  the 
form  of  inhaled  spray  ;  and  to  five  others  by  rectal  injection. 
All  the  experiments  were  negative.  Yet  they  should  have 
succeeded  if  we  suppose  that  the  plasmodia  live  in  such  water 
and  infect  either  by  the  respiratory  or  digestive  passages — 
unless  we  assume  that  they  died  in  the  water  during  transit 
to  Rome,  where  the  experiments  were  conducted. 

In  1895-1896  I  made  twenty-two  experiments  with  a  view 
to  infecting  healthy  persons  with  drinking  water  in  which 
mosquitos  had  been  allowed  to  lay  their  eggs  and  die  [1896]. 
The  first  case  was,  by  a  coincidence,  attacked  with  fever  ;  but 
as  all  the  rest  proved  practically  negative,  I  decided  that 
no  reliable  evidence  had  been  obtained  one  way  or  the 
other. 

A.  Bignami,  in  a  paper  discussing  Manson's  hypothesis 
[1896],  stated  that  he  had  failed  some  time  previously  in 
causing  infection  by  the  bites  of  mosquitos  brought  from 
malarious  places.  He  believed  with  King  that  the  insects 
bring  the  poison  from  the  marsh,  and  I  presume  that  his 
mosquitos  were  therefore  collected  at  random.  This  hypothesis 
was  not  in  accordance  with  parasitological  teaching. 

The  first  correct  experiments  on  mosquito-inoculation  were 
performed  by  myself  in  August  1896.  At  that  time  I  began 
to  abandon  part  of  Manson's  hypothesis  according  to  which 
the  insects  take  the  parasites  from  man  and  deposit  them  in 
water — I  began  to  think  that  the  insects  take  the  parasites 
from  man  and  also  inoculate  them  into  man.  A  number  of 
several  kinds  of  Culex  and  Stegomyia  were  therefore  allowed 
to  feed  on  various  cases  of  malaria — one  of  which  contained 
all  the  three  species  of  parasites — and  were  then  fed,  after  being 
kept  for  several  days  and  on  several  occasions,  upon  Mr  Appia, 
Assistant  -  Surgeon  to  my  hospital  in  Bangalore,  India.  The 
result    was    entirely    negative,    the    mosquitos    being    of    the 


17]  MOSQUITO    INOCULATIONS  79 

wrong  kinds,  and  the  interval  between  the  feedings  too  short 
[30th  October  1896]. 

The  first  successful  mosquito  inoculations  were  those  of 
birds,  Calcutta,  June  to  August  1898.  Four  sparrows  and  a 
weaver-bird,  which  had  frequently  been  found  to  contain  no 
parasites,  and  had  been  often  used  for  controls  in  my  laboratory 
for  that  reason,  were  bitten  towards  the  end  of  June,  on  several 
nights  in  succession,  by  numbers  of  Ctilex  fatigans  heavily 
infected  with  P.  danilevskyi.  On  9th  July  they  were  all  found 
to  contain  "swarms  of  the  parasites."  The  experiment  was 
next  repeated  on  many  more  birds  under  proper  conditions, 
with  the  following  results : — 

(i).  Out  of  twenty-eight  healthy  sparrows  twenty-two  or 

79%  were  infected  in  this  manner. 
(2).  One  of  the  six  sparrows  that  escaped  the  first  experi- 
ments was  infected  on  a  second  trial  (the  remainder 

died). 
(3).  Out  of  two  crows  and  four  weaver  -  birds,  free   from 

P.  danilevskyi,  one  of  the  crows  and  all  the  others 

became  infected. 
(4).  Out  of  five  sparrows,  originally  containing  a  very  few 

P.  danilevskyi,  four  showed  a   much   more  copious 

infection  after  the  experiments. 
The  experiments  were  quite  decisive.  At  that  time  in 
Calcutta  I  found  these  parasites  only  in  fifteen  out  of  one  hundred 
and  eleven  wild  sparrows,  and  then  only  in  small  numbers  in 
the  blood.  But,  as  I  used  large  numbers  of  heavily  -  infected 
mosquitos,  the  produced  infections  were  extremely  copious,  as 
many  as  ten  to  sixty  parasites  being  counted  in  each  field  of 
the  microscope  (oil-immersion  lens).  The  incubation  period 
was  always  four  to  seven  days.  This  success  was  reported  in 
England  by  telegram,  and  was  published  by  Manson  at  the 
end  of  July  1898. 

The  following  experiments  have  subsequently  been  per- 
formed on  men. 


8o  OBSERVATIONS   AND    EXPERIMENTS  [Sect. 

Case  I.  Bignami  [November  1898].  —  Some  months  later 
Bignami  succeeded  in  infecting  a  man  by  following  my  methods. 
A  number  of  mosquitos  caught  in  infected  houses  at  Maccarese 
were  fed  on  a  malaria-free  inmate  of  the  Santo  Spirito  Hospital, 
situated  in  a  part  of  Rome  where  there  is  no  malaria.  They 
were  fed  on  him  nightly  from  26th  September  to  the  end  of 
October  1898,  and  belonged  to  Anopheles  inaculipenms,  and  two 
species  of  Culicines.  The  subject  was  attacked  with  slight 
fever  on  31st  October,  and  severe  fever  the  next  two  days  ; 
quinine  being  given  on  3rd  November,  In  spite  of  careful  search, 
the  parasites  (malignant)  were  not  found  until  3rd  November, 
about  forty  hours  after  the  first  marked  rise  of  temperature. 
Several  relapses  occurred  later. 

Case  2.  Bastianelli,  Bignami  and  Grassi  [1898- 1899]. — 
Anopheles  niaculipennis  caught  at  Maccarese  were  fed  from 
13th  November  to  2nd  December  1908,  on  a  healthy  subject 
in  the  same  hospital.  Fever  commenced  on  3rd  December  and 
continued  daily  until  9th  ;  quinine  on  the  7th.  Mild  tertian 
parasites  found  on  first  day  of  fever.  Parasites  found  also 
in  the  mosquitos. 

Note, — This  fortunate  experiment  revealed  that  the  tertian 
parasites  also  are  carried  by  A.  niaculipennis. 
Gametids  appeared  on  6th  December. 

Case  3.  Ibid. — Seven  A.  niaculipennis  caught  in  an  infected 
house  at  Tre  Fontane  were  fed,  each  one  once,  on  loth,  nth, 
13th  December  1898  on  a  subject  in  the  same  hospital.  The 
protospores  were  found  in  the  salivary  glands  of  two  out  of 
three  of  these  insects  examined.  Subject  attacked  with  fever 
on  29th  December,  the  mild  tertian  parasites  being  found  next 
day — two  sets.     Gametids  on  the  31st. 

Case  4.  Ibid. — Three  A.  inaculipennis  were  fed  on  a  case 
of  crescents  between  loth  to  i8th  December  1898,  were 
incubated  at  30""  C,  for  two  days,  and  were  then  re-fed  on  a 


17]  MOSQUITO   INOCULATIONS  8i 

healthy  subject  on  2nd  and  5th  January  1899.  All  three 
mosquitos  were  found  to  be  infected,  and  two  of  them  had 
protospores  in  their  salivary  glands.  Subject  was  attacked  with 
fever  from  14th  to  i8th  January.  Quinine  on  i6th.  Malignant 
parasites  found  on  15th  and  disappeared  under  quinine  on 
17th,     No  crescents  found. 

Case  5.  P.  Manson  [1900]. — Ten  A,  viaculipennis  were  fed 
on  a  case  of  double  benign  tertian  in  Rome  on  17th,  20th, 
23rd  August  1900,  and  bit  P.  Thorburn  Manson  in  London 
on  29th  and  31st  August,  and  2nd  and  4th  September.  Also 
thirty-five  of  same  species  were  fed  on  a  simple  benign  tertian 
case  in  Rome  on  6th  and  7th  September,  and  on  the  same 
healthy  subject  in  London  on  loth  and  12th  September.  Fever 
began  on  13th  September,  and  continued  on  14th,  15th,  i6th 
and  17th.  Benign  tertian  parasites  found  on  i6th  for  the  first 
time.     Quinine  on  17th.     Relapse  nine  months  later. 

Case  6.  Rees  [October  1900].  —  A  second  subject,  Mr 
Warren,  was  bitten  by  the  second  batch  of  mosquitos  fed  on 
previous  subject  at  about  the  same  time  (not  given).  Fever 
commenced  on  28th  September  after  about  fourteen  days'  incuba- 
tion, and  seemed  to  have  continued  for  some  time.  Parasites 
in  phagocytes  on  30th.  Benign  tertian  parasites  on  2nd  October 
and  subsequently.  Quinine  on  3rd.  Author  says  that  this 
case  showed  more  parasites  than  the  previous  one,  as  he  was 
bitten  by  more  mosquitos. 

Case  7.  Fearnside  [1901]. — The  following  series  of  seven 
cases  were  obtained  at  Rajamundri,  India,  in  i9(X)-i90i.  Un- 
fortunately, the  Anophelines  were  not  identified,  but  the  author 
states  that  only  one  species  was  used.  Source,  benign  tertian, 
copious,  sporulating  on  17th  December,  when  the  Anophelines 
were  fed.  Insects  were  re-fed  on  the  author  himself  on  20th 
December  and  ist  and  8th  January  1901.  Tertian  fever  began 
on  the  14th.  Benign  tertian  parasites  found  on  18th.  No 
quinine. 

F 


82  OBSERVATIONS   AND   EXPERIMENTS  [Sect. 

Note. — Author  had  suffered  from  mahgnant  malaria  with 
haemoglobinuria  in  1891 ;  but  that,  apparently, 
did  not  affect  the  present  experiment. 

Case  8.  Fearnside  [1901]. — Source  the  same,  and  Anophelines 
fed  on  same  date.  Subject  (an  Indian)  bitten  on  28th  December. 
Tertian  fever  on  iSth  January.  Benign  tertian  parasites  on 
2ist. 

Case  9.  Ibid.  —  Sources,  two  cases  of  benign  tertian. 
Anophelines  fed  12th  and  13th  December.  Bit  subject  (Indian) 
on  27th.  Benign  tertian  on  nth  January.  Benign  tertian 
parasites  on  13th.  In  notes,  author  says  that  only  one 
Anopheline  inoculated  the  subject. 

Case  10.  Ibid. — The  same  source.  Anophelines  infected 
1 2th  December  and  bit  subject  (Indian)  on  26th.  Tertian 
fever  on  20th  January,  and  tertian  parasites  on  25th.  Apparently 
the  same  (one)  mosquito  used  as  in  previous  case. 

Case  II.  Ibid. — Source,  double  infection  of  malignant  and 
of  benign  tertian.  Anophelines  infected  i6th  December,  and 
bit  subject  (Indian)  on  28th.  Fever  on  9th  January,  and 
malignant  parasites  on  nth;  doubtful  tertian  parasites  on  12th. 

Case  12.  Ibid. — Same  source.  Anophelines  fed  on  same 
date  and  bit  subject  (Indian)  on  28th  December.  Fever,  13th 
January.     Malignant  and  benign  tertian  parasites  on  14th. 

Note. — Of  two  other  cases  experimented  with  by  Fearnside 
one  appears  to  have  failed,  and  one  to  have 
contracted  fever  after  fifteen  days,  the  finding 
of  the  parasites  not  being  noted.  Author  states 
that  protospores  were  found  in  all  the  Anophe- 
lines used. 

Case  13.  Buchanan  [1903]. — Experiments  done  at  Nagpur, 
India.  Source,  malignant.  Anophelines  (species  not  given) 
fed  25th  December  1901  to  8th  January  1902,  and  bit  subject 


17]  MOSQUITO   INOCULATIONS  83 

loth    to    17th   January.     Fever    27th   January,  and   malignant 
parasites. 

Case  14.  Buchanan  [1903]. — Source,  malignant.  Anophe- 
lines  fed  13th  to  23rd  January  1902,  and  bit  subject  24th  to  27th 
January.     Fever  12th  February,  and  malignant  parasites. 

Case  15.  Ibid. — Source,  malignant.  Anophelines  fed  24th 
January  to  4th  February  1902,  and  bit  subject  7th  to  19th 
February.     Fever  19th  February,  and  malignant  parasites. 

Case  16.  Ibid. — Source,  malignant.  Anophelines  fed  27th 
January  to  4th  February  1902,  and  bit  subject  4th  to  20th 
February.     Fever  23rd  February,  and  malignant  parasites. 

Case  17.  Ibid. — Source,  malignant.  Anophelines  fed  29th 
January  to  nth  February  1902,  and  bit  subject  12th  to  23rd 
February.     Fever  3rd  March,  and  malignant  parasites. 

Note. — Three  attempts  to  infect  from  malignant  sources 
failed.  In  two  other  cases,  however,  there  was 
no  fever  after  the  mosquito  inoculations,  but 
crescents  were  found  after  twelve  and  eight  days. 
These  are  not  accepted  here. 

Case  18.  Ibid. — Source,  quartan.  Anophelines  (?  species) 
fed  30th  January  to  nth  February  1902  ;  and  bit  subject  from 
14th  to  27th  February.  Fever  25th,  and  malignant  parasites 
{not  \.\\os,&  foimd  in  source). 

Note.  —  Four  other    cases    from    quartan    sources    failed. 
Anophelines  not  identified. 

Case  19.  Ibid. — Source,  benign  tertian.  Anophelines  fed 
8th  to  20th  January  1902,  and  bit  subject  21st  to  25th  January. 
Fever  4th  February,  and  benign  tertian  parasites. 

Case  20.  Ibid. — Source,  benign  tertian.  Anophelines  fed 
15th  to  25th  January  1902,  and  bit  subject  28th  January  to 
I  oth  February.  Fever  15th  February,  and  malignant  parasites 
{not  XhosQ  found  in  source). 


84  OBSERVATIONS  AND   EXPERIMENTS  [Sect. 

Case  2 1 .  Buchanan  [1903]. — Source,  benign  tertian.  Anophe- 
lines  fed  ist  to  13th  February  1902,  and  bit  subject  15th  to  25th 
February.     Fever  23rd  February,  and  benign  tertian  parasites. 

Case  22.  Ibid. — Source,  benign  tertian.  Anophelines  fed  2nd 
to  14th  February  1902,  and  bit  subject  17th  to  22nd  February. 
Fever  ist  March,  and  benign  tertian  parasites. 

Note. — Five  other  attempts  to  infect  from  tertian  sources 
failed. 

Case  23.  Schiiffner  [1902]. — Experiments  in  Sumatra  with 
two  species  of  Anophelines,  apparently  Cellia  kochii  Donitz, 
and  a  Myzomyia.  Source,  benign  tertian.  Anophelines  fed  (?) 
15th  July  (?)  1902,  and  bit  subject,  the  author  himself,  on 
two  days  (?)  25th  July.  Fever,  double  tertian,  nth  August 
and  benign  tertian  parasites. 

Case  24.  Ibid. — Same  source,  and  Anophelines  fed  same 
date,  and  bit  another  subject  on  same  date.  Fever  on  same 
date,  single  tertian  ;  and  tertian  parasites. 

Case  25.  Ibid. — Source,  malignant.  Infected  Anophelines 
bit  subject  (Chinaman)  on  20th,  21st  August  (?)  1902.  Fever 
5th  September,  and  malignant  parasites  7th. 

Case  26.  Jancso  [1905].  —  A  long  series  of  admirable 
experiments  on  the  effect  of  temperature  on  the  development 
of  the  parasites  in  Anopheles  inaculipen?iis  \  carried  out  at 
Kolozsvar,  Hungary,  Source,  benign  tertian.  Six  Anopheles 
fed  23rd  September  (?)  1904,  and  kept  at  21°  C.  for  twenty- 
three  days.  Subject  bitten  i6th  October,  had  fever  on  15th  day. 
Benign  tertian  parasites  on  i6th  day. 

Case  27.  Ibid. — Source,  malignant.  Fifty-two  Anopheles 
fed  26th  October  (?)  1904,  kept  at  30°  C,  and  bit  subject  3rd  to 
13th  November.     Fever  15th  ;  malignant  parasites  i6th. 

Case    28.      Ibid. — Same    source.      Anopheles    fed    on    29th 


17]  MOSQUITO   INOCULATIONS  85 

October  and  kept  at  30''  C.  Subject  bitten  6th  to  8th  November 
by  more  than  twelve.  Fever  i6th,  and  malignant  parasites 
on  1 8th. 

Case  29.  Jancso  [1905]. — Same  source,  and  mosquitos. 
Subject  bitten  by  six  on  i6th  November.  Fever  22nd,  and 
malignant  parasites  26th. 

Case  30.  Ibid. — Source,  malignant.  Anopheles  fed  15th 
November  and  kept  at  22-24''  C.  Subject  bitten  by  seven  on 
30th.     After  ten  days,  fever  and  malignant  parasites. 

Case  31.  Ibid. — Same  source  and  mosquitos.  Subject 
bitten  by  one  Anopheles  on  3rd  December.  After  fourteen 
days,  crescents  in  blood. 

Case  32.  Ibid. — Same  source  and  mosquitos.  Subject 
bitten  on  6th  December  by  two  Anopheles.  Quinine  1-2 
grams  on  12th  and  13th.  Fever  and  malignant  parasites  on 
18th. 

Case  33.  Ibid. — Source,  malignant.  Anopheles  fed  24th 
September  at  30^  C,  and  afterwards  kept  at  20°  C.  Subject 
bitten  on  21st  October  by  one  Anopheles,  strongly  infected. 
Quinine  i  gram  on  28th  and  29th.  Fever  on  4th  November 
and  crescents  on  6th. 

Case  34.  Ibid. — Source  malignant.  Anopheles  fed  24th 
September  and  ist  October  at  30"  C,  and  then  kept  at 
15-17°  C.  Subject  bitten  7th  November  by  two  of  these  with 
glands  infected.     Fever  and  crescents  on  iSth. 

Case  T^^.  Ibid. — Same  source.  .^4«<7//z^/^j  fed  25th  September 
and  ist  October  and  kept  at  varying  temperatures  from  8-30'  C. 
Subject  bitten  by  two  of  these  (both  infected)  on  13th  and  iSth 
October.     Fever  24th  and  crescents  25th. 

All  these  cases  have  been  verified  by  me  in  the  original 
literature ;  but  there  are  probably  some  other  experiments 
which  have  been  overlooked.^ 

'  See  section  65  (5). 


CHAPTER  IV 

THE   PARASITIC   INVASION    IN    MAN 

18.  The  Onset  of  the  Invasion. — It  does  not  lie  within  the 
province  of  this  book  to  give  a  full  description  of  the  pathology 
and  symptoms  of  malarial  fever — a  subject  which  is  dealt  with 
in  many  works.  But  before  proceeding  to  our  proper  theme, 
we  shall  do  well  to  examine  a  certain  number  of  questions, 
especially  some  upon  which  little  stress  has  been  laid  in  the 
publications  referred  to.  We  should  begin  by  attempting  to 
obtain  a  clear  picture  of  the  onset  and  progress  of  the 
parasitic  invasion  in  man. 

Our  first  care  should  be  to  consider  the  number  of  organisms 
engaged  in  the  invasion — a  subject  which  has  been  much 
neglected.  For  example,  in  the  eighty-six  cases  of  successful 
experimental  inoculations  of  men,  I  cannot  find  a  single  one 
in  which  correct  estimates  of  the  number  of  parasites,  in  the 
source,  the  carrier,  or  the  subject,  have  been  even  attempted. 
Certainly,  these  experiments  prove  the  main  theorem,  that 
the  parasites  cause  the  disease  ;  but  they  might  easily  have 
been  used  to  obtain  many  valuable  pathological  data  in 
addition.  We  are  thus  forced  (at  present)  to  rely  largely 
upon  calculation  for  our  figures. 

(i).  The  imviber  of  parasites  in  the  mosquito. — The  number 
of  parasites  which  enter  a  mosquito  when  it  feeds  on  a  patient 
depends  {a)  on  the  amount  of  blood  sucked  up  by  it,  and  {b)  on 
the  number  of  parasites  in  that  blood.  The  insects  feed  during 
variable  periods — for  a  few  seconds   if  disturbed,  or  perhaps 

86 


Sect.  i8]  ONSET   OF    INVASION  87 

during  the  whole  night  upon  a  sleeping  person.  While  feeding 
they  void,  every  ten  seconds  or  so,  some  of  the  fluid  part  of 
their  meal  ;  so  that  during  a  whole  night  they  may  possibly 
consume  much  more  blood  than  one  stomach-full.  A  mosquito 
fully  gorged  in  this  manner  may  (perhaps)  consume  several 
cubic  millimetres  of  blood.  It  would  be  easy  to  settle  this 
point  by  allowing  a  number  of  mosquitos  to  feed  during 
I,  2,  3,  4  .  .  .  minutes,  and  then  killing  and  weighing  them 
and  their  dejecta.  For  example,  as  R.  Newstead  has  shown 
("Reports  Li  v.  Sch.  Trop.  Medicine,  Liverpool,"  1905,  vol.  xvii. 
p.  25),  the  tick  Ornithodorus  tnoubata  weighs  0*027  grams 
before  feeding  and  o'26o  grams  after  feeding.  D.  Thomson 
and  myself  find,  in  researches  now  being  conducted  in  my 
clinic  in  Liverpool,  that  6-7000  crescents  per  c.mm.  of  blood 
is  not  an  exceptionally  high  number.  Supposing  that  only 
half  of  these  are  females,  it  is  still  very  unlikely  that  so  many 
could  ever  develop,  after  being  fertilised,  in  one  insect — a  large 
or  very  large  proportion  probably  perish  from  phagocytosis  and 
other  causes  in  the  stomach  contents.  The  largest  number  of 
developing  zygotes  found  by  me  in  one  insect  {C.  fatigans 
gorged  on  blood  with  P.  danilevskyi)  was  445.  Ten  of  these 
mosquitos  fed  all  night  on  a  bird  with  moderate  parasites 
(i/iooo  haematids)  were  found  to  contain  an  average  of  29 
zygotes  each  ;  and  ten  of  them  fed  on  a  bird  with  many 
parasites  (1/50  haematids)  contained  an  average  of  100  zygotes 
each  [May  1898].  But  I  do  not  know  what  proportion  of  the 
parasites  in  these  birds  were  sexual  forms.^  The  number 
of  zygotes  found  in  Anophelines  naturally  fed  on  human 
blood  does  not  very  often,  I  think,  exceed  fifty — but  this  is 
probably  due  to  the  manner  of  feeding.  The  number  of 
ingested  sexual  parasites  which  reach  maturity  and  develop 
protospores  depends  {a)  on  the  susceptibility  of  the  insect,  {b) 
on  the  temperature,  and  {c)  possibly  many  other  conditions. 
Jancso  [1905]  finds  that  the  zygotes  develop  best  at  24-30°  C, 
^  See  reference  to  paper  by  S.  T.  Darling  in  section  65. 


88  THE  PARASITIC   INVASION   IN   MAN  [Sect. 

temperatures  above  and  below  these  limits  retarding  the  process 
(A.  macidipennis)  \  and  that  they  die  if  the  mosquito  is  kept 
constantly  below  i6'  C.  after  feeding.  On  the  other  hand,  they 
often  continue  to  grow  if  the  carrier  is  subjected  merely  to  an 
intermittent  low  temperature.  Regarding  the  susceptibility  of 
various  species  of  mosquitos  much  work  remains  to  be  done. 

(2).  The  number  of  protospores  in  the  salivary  glands. — I  may 
have  overlooked  references,  but  do  not  know  that  the  average 
number  of  protospores  in  matured  zygotes  has  ever  been 
exactly  estimated.  I  should  give  the  number  (merely  as  an 
impression)  at  about  a  thousand.  Not  all  of  these  effect  an 
entry  into  the  salivary  glands.  Here,  again,  there  seem  to  be 
no  exact  counts.  I  fancy  that  more  than  10,000  of  them  will 
seldom  be  found  in  the  glands  of  a  single  Anopheline,  while 
often  there  may  perhaps  be  only  a  few  hundreds  at  a  time 
(subject  to  correction). 

(3).  How  many  protospores  enter  the  human  blood? — This 
must  depend  (a)  upon  the  number  of  spores  in  the  biting 
insect's  salivary  gland,  and  {b)  upon  the  number  of  times  it  is 
allowed  to  bite  its  victim.  I  think  that  mosquitos  inject  their 
poison  before  commencing  to  suck.  If  this  is  the  case,  an 
insect  which  bites  a  person  several  times  (as,  for  instance,  when 
he  is  asleep)  is  likely  to  inoculate  many  more  protospores  than 
one  which  succeeds  in  biting  only  once.  In  the  former  case 
several  thousand  spores  may  perhaps  be  introduced ;  in  the 
latter  case  perhaps  only  a  few. 

But  not  all  of  the  spores  which  have  entered  are  likely  to 
live.  Probably  many  perish  by  falling  outside  the  blood  stream 
or  by  becoming  a  prey  to  phagocytes. 

(4).  Further  development  of  the  protospores. — F.  Schaudinn 
observed  that  if  protospores  are  taken  from  a  mosquito's 
salivary  gland  and  are  mixed  with  blood  under  the  microscope, 
many  of  them  may  actually  be  watched  entering  the  haematids, 
where  they  become  the  young  intracorpuscular  parasites  familiar 
to  students.     These  now  begin  to  grow  and  to  develop  a  second 


i8]  ONSET  OF   INVASION  89 

generation  of  spores,  which  should  be  called  deutevospores.  The 
latter  attack  fresh  haematids,  within  which  they  grow,  and 
develop  a  third  generation  of  spores,  which  we  may  call 
tritospores ;  and  so  on  indefinitely. 

(5 ).  The  number  of  spores  produced  by  each  species  of  parasite. — 
The  parasites  of  malaria  are  described  in  detail  in  the  text- 
books. Since  the  time  of  Golgi,  all  observers  admit  that 
they  belong  to  three  types  at  least,  each  of  which  differs 
morphologically,  and  markedly  so,  from  the  others.  I  assume, 
for  the  sufficient  reasons  frequently  given,  that  these  three 
types  are  three  different  species.  The  number  of  spores  pro- 
duced by  each  species  is  variable,  and  different  authors  give 
different  figures  (probably  the  number  has  never  been  accurately 
estimated).  I  adopt  the  following  names  and  figures  for  the 
present : — 

Plasmodium  malariae  Laveran,  1881.  The  Quartan  Parasite  ; 
produces  say  6-12  spores  every  three  days. 

Plasmodium  vivax  Grassi  and  Feletti,  1890.  The  Benign 
Tertian  Parasite  ;  produces  say  15-20  spores  every  two  days. 

Plasmodium  falciparum  Welch,  1897.  The  Malignant 
Parasite  ;  produces  say  6-20  or  more  spores  every  two  days. 

Some  authors  consider  that  there  are  two  if  not  three 
varieties  (or  ?  species)  of  malignant  parasites.  I  am  inclined 
to  agree  with  them,  but  have  not  yet  satisfied  myself 
sufficiently  on  the  point  to  admit  it  in  my  classification. 

(6).  The  onset  of  the  invasion.  —  Let  us  suppose  that  a 
mosquito  has  inoculated  several  thousand  protospores,  but  that 
only  one  thousand  of  these  have  succeeded  in  entering  the 
haematids.  After  two  or  three  days,  according  to  the  species 
of  parasite,  each  will  produce  a  variable  number  of  deutero- 
spores.  But,  probably,  not  all  of  these  will  succeed  in  infecting 
fresh  haematids ;  many  may  be  devoured  by  phagocytes,  or  be 
destroyed  by  other  agencies,  while  passing  from  one  haematid  to 
another.  And  the  same  thing  is  likely  to  happen  with  every 
successive  generation  of  spores.     Hence  only  a  proportion  of 


90  THE   PARASITIC   INVASION    IN   MAN  [Sect. 

the     spores     actually     produced    are     likely    to     enter    fresh 
corpuscles. 

Suppose  that  i,ooo  protospores  of  P.  vivax  have  entered 
haematids,  and  that,  on  the  average,  only  lo  out  of  the  15-20 
spores  actually  produced  in  the  successive  generations  succeed 
in  entering  fresh  haematids.  The  parasites  should  then  multiply 
as  follows  : — 

No.  of  days  024  6 

No.  of  parasites  1,000  10,000  100,000  1,000,000 

No.  of  days  8  10  12 

No.  of  parasites  10,000,000  100,000,000  1,000,000,000 

and  so  on. 

In  the  case  of  P.  malariae  the  multiplication  should  be 
slower,  if  the  number  of  spores  given  above  is  correct.  But 
in  that  of  P.  falciparum  the  data  are  too  uncertain  for 
calculation. 

(7).  The  number  of  haematids  in  an  average  man. — According 
to  accepted  standards  we  have — 

{a)   I  c.mm.  of  blood  contains  5,000,000  haematids. 
{b)  The  specific  gravity  of  blood  (male)  is  about  I057"5. 
(<:)    The  total  amount  of  blood  weighs  about  4-9/100  of  the 
total  weight  of  the  body.^ 

From  these  data  we  calculate  that  3,000,000  c.mm.  of  blood 
weigh  3" 1 7  kilograms,  and  will  be  contained  in  a  man 
weighing  6474  kilograms  (142  lbs.  English,  or  about  10  stone), 
and  that  these  3,000,000  c.mm  will  contain  15,000,000,000,000 
haematids. 

This  may  then  be  taken  as  the  normal  number  of  haematids 
in  an  average  healthy  man  of  about  64  kilograms,  or  10  stone, 
in  weight.  The  reader  should  endeavour  to  form  some  tangible 
idea  of  this  enormous  number.  If  he  were  to  try  to  count  it  at 
the  rate  of  100  a  minute  day  and  night  without  cessation,  he 
would  have  to  spend  285,000  years  over  the  task  ! 

^  The  ratio  of  blood  to  body  weight  was  formerly  estimated  at  about  1/13,  but  the 
estimate  has  recently  been  reduced  in  consequence  of  better  methods  of  measurement. 


i8]  FEVER-PRODUCING   NUMBER  91 

(8).  The  lowest  number  of  parasites  required  to  produce  the 
first  illness. — We  can  scarcely  imagine  that  one  protospore,  or 
even  many  thousands  of  these  minute  bodies,  can  produce  any 
marked  symptoms  in  the  patient ;  and,  in  fact,  we  learn  from 
the  fundamental  experiments  that  as  a  rule  no  symptoms 
appear  for  some  days  after  the  moment  of  inoculation — this 
period  being  commonly  called  the  incubation  period.  But  as 
the  parasites  increase  at  every  generation,  a  time  must  come 
when  the  number  of  them  will  suffice  to  cause  illness.  Can  we 
determine  this  number?  No  serious  attempt  has  yet  been 
made  to  do  so,  or,  indeed,  to  find  any  exact  correlation  between 
the  number  of  parasites  and  the  amount  of  sickness.  There 
are  many  difficulties  in  the  way.  It  is  not  always  easy  to 
estimate  the  number  of  parasites,  and  still  less  to  know  when 
precisely  the  illness  commences.  In  most  of  the  experimental 
inoculations,  some  illness,  or  even  sharp  fever,  has  occurred 
before  any  parasites  have  been  found  by  the  microscope.  On 
the  other  hand,  Elting  has  been  able  to  find  the  parasites  in 
some  of  his  cases  before  the  onset  of  the  fever.  The  question 
is  probably  determined  partly  by  the  skill  and  patience  of  the 
observer,  partly  by  the  susceptibility  of  the  patient,  and  partly 
by  the  "  virulence  "  of  the  parasites.  A  laborious  search  may 
reveal  the  parasites  when  they  are  comparatively  few  in 
number  ;  and  on  the  other  hand,  a  patient  who  has  never  been 
previously  infected  will  probably  begin  to  suffer  earlier  during 
the  course  of  the  invasion  than  one  who  is  partially  "  immune." 
But  for  a  broad  general  rule  we  may,  I  think,  accept  the 
principle  (pending  more  exact  researches)  that  if  we  cannot 
find  the  parasites  after  careful  search,  their  number  is  not 
usually  sufficient  to  produce  fever.  Hence  I  calculate  that  they 
will  not  generally  be  numerous  enough  to  cause  illness  unless 
there  is  at  least  one  parasite  to  100,000  haematids ;  that  is, 
50  parasites  in  i  c.mm.  of  blood;  or  150,000,000  in  a  man  of 
10  stone  (64  kilograms^  in  weight. 

(9).    The  time  required  to  examine  blood  microscopically. — It 


92  THE   PARASITIC   INVASION   IN   MAN  [Sect. 

is  very  necessary  to  have  clear  ideas  upon  this  point.  Suppose 
that  the  diameter  of  a  "  field "  seen  by  an  oil-immersion 
Objective  and  a  No.  2  Ocular  measures  0*165  mm.,  or  nearly 
i/6th  of  a  millimetre.  Then  by  moving  the  specimen  across 
this  field  of  vision,  searching  it  as  we  move  it,  we  shall  cover, 
after  traversing  sixty  times  the  diameter,  a  strip  nearly  ro 
centimetre  long,  and  0"Oi65  cm.  broad.  Examining  strip 
after  strip  in  the  same  way,  when  we  have  examined  sixty 
strips  we  shall  have  covered  nearly  one  square  centimetre 
of  area. 

The  time  required  for  this  will  depend  upon  the  care 
with  which  we  must  examine  the  successive  fields  as  they 
pass  under  the  eye.  If  we  can  search  at  the  rate  of  twenty 
fields  a  minute,  we  can  search  a  whole  strip  in  three  minutes 
and  a  whole  square  centimetre  in  three  hours.  If  the  object 
is  large  and  easily  visible  we  shall  be  able  to  move  the 
specimen  faster  than  this  ;  if  it  is  small  and  delicate,  the 
observer  must  be  fairly  expert  to  search  so  quickly. 

Now  suppose  that  we  must  examine  a  thin  film  of  liquid 
blood  spread  under  a  coverglass.  If  the  average  depth  of 
the  film  is  only  0*00025  mm.  (2*5^  or  about  1/3  the  diameter 
of  haematid),  then  i  c.mm.  of  the  blood  will  be  spread  out 
under  4  sq.  cm.  of  area  —  that  is,  over  the  whole  area 
occupied  by  a  square  coverglass  of  2  cm.  side.  To  do  this 
will  require  twelve  hours'  continuous  work.  If  the  average 
depth  of  the  film  is  3*3 3/u  the  c.mm.  of  blood  will  cover  a  space 
of  3  sq.  cm.,  requiring  nine  hours'  search ;  but  in  this  case  we 
shall  be  more  liable  to  overlook  small  objects,  though  we 
shall  more  easily  find  large  ones. 

With  an  average  depth  of  2*5/x,  i  sq.  cm.  of  film  will 
normally  contain  1,250,000  haematids.  One-sixtieth  of  this, 
that  is,  one  strip  as  defined  above,  will  contain  20,833 
haematids ;  so  that,  if  we  are  fairly  expert,  we  should  be  able 
to  search  6,944,  ^^  ^^Y  7)000  haematids  a  minute.  With  an 
average  depth  of  3'S3/m,  i  sq.  cm.  of  film  will  contain  1,666,666 


i8]  TIME  REQUIRED   FOR   SEARCH  93 

haematids,  which  can  be  searched  at  the  rate  of  9,259  haematids 
a  minute.  In  the  former  case  a  single  circular  field  of  the 
microscope,  165^  in  diameter  (area  0*0209  sq.  mm.),  will 
contain  an  average  of  about  261  haematids.  In  the  latter 
case  it  will  contain  about  345  haematids  on  the  average. 
There  are,  of  course,  more  than  3,600  squares  of  165^  side 
in  a  square  centimetre;  and  therefore  four  and  three  times 
this  number  of  squares  must  be  examined  to  search  i  c.mm. 
of  blood  in  films  of  2'5/ji  and  3'33^t  in  depth  respectively.  If 
we  could  examine  the  squares  at  a  rate  so  fast  as  one  a 
second,  three  to  four  hours  would  still  be  required  to  search  i 
c.mm.  completely.  To  search  the  whole  of  the  3,000,000  c.mm. 
of  blood  contained  in  a  man  of  about  10  stone  in  weight  would 
therefore  take,  at  the  quickest  rate,  more  than  1,027  years. 

I  have  just  estimated  roughly  that  the  parasites  will 
probably  be  numerous  enough  to  cause  fever  if  they  number 
1/100,000  haematids.  If  it  requires  twelve  hours  to  search 
I  c.mm.  of  blood  containing  5,000,000  haematids,  100,000 
haematids  can  be  searched  in  a  little  less  than  fifteen 
minutes ;  so  that  if  the  parasites  are  so  few  as  this  we  can 
expect  to  find  them  at  the  rate  of  about  one  every  quarter  of 
an  hour.  But  chance  intervenes  here :  if  we  are  lucky  we  may 
find  the  first  parasite  almost  at  once ;  if  we  are  unlucky  we 
may  have  to  search  several  hundreds  of  thousands  of  haematids 
before  finding  an  infected  one.  There  is  always  the  danger  of 
overlooking  a  plasmodium  even  when  it  should  have  been  seen. 

In  a  dry  stained  film  the  blood  is  spread  out  over  a  wider 
area,  so  that  there  are  only  about  150-200  haematids  in  a 
circular  field  of  165/ji.  I  think  therefore  that  the  larger 
pigmented  parasites  are  less  quickly  found  in  such  than  in 
liquid  films ;  but  on  the  other  hand,  the  smaller  plasmodia, 
being  characteristically  coloured,  are  detected  with  much  greater 
certainty — as  Marchoux  showed  [1897].  On  the  whole,  I  think 
that  the  two  methods  are  about  equal  in  diagnostic  value. 

In    my    "thick-film"    process    [1903],    i    c.mm.    of    blood 


94  THE   PARASITIC    INVASION    IN   MAN  [Sect. 

occupies  only  about  i/Sth  of  a  sq.  cm.  of  area,  or  less,  so  that 
there  should  be  twenty  to  thirty  times  more  haematids  and 
parasites  per  field.  But  the  latter  require  more  skill  for 
detection  (section  65). 

Such  calculations  demonstrate  the  absurdity  of  supposing 
that  there  are  no  plasmodia  present  in  a  person  because  we 
fail  in  finding  one  after  a  few  minutes'  search.  As  a  matter 
of  fact,  even  if  as  many  as  150,000,000  plasmodia  are  present 
in  an  average  man,  the  chances  are  that  ten  to  fifteen  minutes' 
search  will  be  required  for  each  plasmodium  found  ;  while  if 
we  are  careless  or  unfortunate  we  may  have  to  look  much 
longer. 

(10).  TJie  period  of  incubation. — To  resume  our  study  of 
the  invasion — we  saw  in  subsection  6  that,  in  the  case  of  P. 
vivax,  1,000  protospores  should  produce  100,000,000  parasites 
in  ten  days  and  1,000,000,000  in  twelve  days.  The  former 
number  would  probably  be  insufficient  to  produce  fever  in  the 
patient,  and  the  latter  would  be  more  than  sufficient.  Hence 
the  illness  would  probably  begin  on  the  twelfth  day  after 
inoculation. 

It  is  usually  thought  that  the  incubation  period  must 
depend  exactly  upon  the  number  of  organisms  injected  either 
by  the  mosquito  or  by  the  experimenter ;  but  this  is  not 
always  correct.  The  proliferation  of  P.  vivax  at  the  rate 
of  ten  spores  at  each  generation  every  second  day,  starting 
with  various  initial  numbers,  should  be  as  follows : — 

No.  of  days  028  10 

{1,000  i  0,000  10,000,000  100,000,000 

2,000  20,000  20,000,000  200,000,000 

3,000  30,000  30,000,000  300,000,000 

10,000  100,000  100,000,000  1,000,000,000 

15,000  150,000  150,000,000  1,500,000,000 

Thus,  starting  with  1,000  protospores,  the  number  of 
parasites  required  to  produce  fever,  namely  150,000,000,  will 
not  be  attained  until  the  twelfth  day.  Starting  with  2,000 
protospores,  this    number   will,  it   is   true,  be   attained   on   the 


i8] 


INCUBATION    PERIOD 


95 


tenth  day,  two  days  earlier;  but  after  this  point  we  shall  have 
to  increase  the  number  of  protospores  originally  injected  up 
to  15,000  before  we  can  reduce  the  incubation  period  by 
another  two  days.  In  other  words,  if  we  estimate  correctly, 
2,000  protospores  should  give  as  long  an  incubation  period 
as  14,000  protospores,  or  seven  times  as  many,  would  give. 
That  is,  it  makes  little  difference  to  the  patient  whether  he 
is  bitten  by  one  or  by  seven  mosquitos,  each  of  which  injects 
2,000  protospores.  I  suppose  that  even  two  or  three  protospores, 
if  they  survive,  would  set  up  infection. 

I  have  assumed  that  P.  vivax  increases  tenfold  at  every 
generation,  but  this  is  a  mere  guess.  The  following  table 
gives  the  first  seven  powers  of  some  natural  numbers  and 
also  the  proliferation  of  a  single  plasmodium  according  to 
various  rates,  from  fivefold  to  twentyfold.  The  party-line 
shows  where  the  numbers,  if  multiplied  by  1,000,  would  reach 
the  fever-point. 


Powers  of  Natural  Numbers. 


5 
6 

7 

25 

36 

49 

64 

81 

100 

121 

144 

169 

196 

225 

400 

125 
216 

343 
512 

729 
1,000 

1,331 
1,728 
2,197 
2,744 
3,375 
8,000  I 

625 

1,296 

2,401 

4,096 

6,561 

10,000 

14,641 

20,736 

28,561 

38,416 

50,625 

160,000 

3,125 

8,776 

16,807 

32,768 

59,049 
100,000 

15,625 

46,656 

117,649 

8 

9 
10 

262,144 

531,441 
1,000,000 

II 
12 
13 
14 
15 
20 

161,051 
248,832 

371,293 
537,824 

659,375 
3,200,000 

1,771,561 
2,985,984 
4,826,809 
7,529,536 
11,390,625 

64,000,000  ] 

78,125  I 


279,936 

823,543 

2,697,152 

4,782,969 

10,000,000 

19,487,171 
33,831,808 
52,748,517 

105,413,504 
170,859,375 

1,280,000,000 


This  table  may  prove  useful  for  estimating  the  average 
rate  of  increase  of  the  various  parasites,  exact  experiments 
upon  which  are  much  needed.  I  think  it  possible  that  more 
spores  may  be  produced  early  in  the  infection  than  later; 
and  also  that  there  is  likely  to  be  a  much  smaller  mortality 
among  the  spores  at  first  than  there  is  later,  when  the 
germicidal  powers  of  the  host  become  (hypothetically)  stronger 


96 


THE   PARASITIC   INVASION    IN   MAN 


[Sect. 


The  following  table  gives  the  incubation  periods  actually 
found  in  the  fundamental  inoculation  experiments  described 
in  sections  14  and  16,  omitting  the  doubtful  results.  The 
cases  are  numbered  as  in  those  sections. 

I.  P.  MALARIAE:  Blood  Inoculations. 


Case 

10 

13 

14 

16 

23 

Quantity  of  blood  c.cm. 

3 

? 

I 

I 

4 

How  injected 

ven. 

ven. 

cut. 

cut. 

ven 

Incubation  (days) 

12 

IS 

17 

12 

II 

Case 

29 

30 

35 

36 

37 

Quantity  of  blood 

2 

2 

4 

4 

4 

How  injected 

cut. 

cut. 

cut. 

cut. 

cut 

Incubation    .... 

16 

II 

25 

25 

25 

{No  JHOsquito  inoculations.) 


2. 

P.    VIVAX: 

Blood  Inoculations 

Case 

8 

9 

18 

19 

20 

21 

Quantity  of  blood  c.cm. 

? 

15 

2 

2 

2 

2 

How  injected 

ven. 

ven. 

? 

? 

? 

? 

Incubation    . 

■ 

II 

II 

12 

12 

10 

10 

Case 

.         . 

22 

34 

41 

42- 

Quantity  of  blood 

3 

0-2 

3 

2 

How  injected 

ven. 

cut. 

ven. 

ven. 

Incubation    . 

6 

21 

3 

5 

3.  p.   VIVAX:   Mosquito  Inoculations. 


Case 

No.  of  mosquitos 

Incubation    . 


9 

ID 

II 

24 

25 

27 

? 

I 

? 

? 

? 

6 

21 

15 

25 

17 

17 

15 

4.  /*.  FALCIPARUM :   Blood  Inoculations. 


Case 

Quantity  of  blood 
How  injected 
Incubation    . 


15 
I '5 
cut. 

15 


17 

cut. 

18 


24 

0*25 
cut. 

12 


25 

2 
? 


26 

5 

? 


27 
07s 


i8] 


INCUBATION   PERIOD 


97 


4.  P.  FALCIPARUM :    Blood  Inoculations. 


Case 

. 

28 

31 

32 

33 

38 

39 

Quantity  of  blood 

02 

2 

? 

? 

15 

1-5 

How  injected 

? 

cut. 

cut. 

cut. 

cut. 

cut 

Incubation    . 

4 

15 

6 

10 

30 

6 

Case 

40 

43 

44 

45 

46 

47 

48 

Quantity  of  blood 

1-5 

I  •5-4-0 

I •5-4-0 

I •5-4-0 

r5-4-o 

I  •5-4-0 

1-5 

How  injected 

cut. 

ven. 

? 

? 

? 

? 

ven 

Incubation    . 

17 

2-5 

4 

7 

4 

3 

5 

5.   p.  FALCIPARUM:   Mosquito  Inoculations. 


Case 

No.  of  mosquitos 

Incubation    . 


26 

30 

31 

33 

34 

35 

? 

6 

7 

2 

I 

2 

15 

6 

10 

12 

14 

II 

From  these  figures  we  collect  the  following  extremes  and 
averages  for  the  incubation  period  in  days  per  case. 


Lowest 

Average 

Highest 

Quartan,  blood  inoculation  . 

II 

17 

25 

Tertian,  blood  inoculation    . 

3 

ID 

21 

„         mosquito  inoculation 

15 

18 

25 

Malignant,  blood  inoculation 

2-5 

8 

30 

„           mosquito  inoculation 

6 

II 

15 

As  we  might  expect,  P.  malai'iae  gives  the  highest  average 
incubation  period,  P.  falciparum  gives  the  lowest,  and  the 
mosquito  inoculations  have  distinctly  longer  periods  than  the 
blood  inoculations. 

The  short  periods  given  by  some  of  the  blood  inoculations 
may  be  easily  explained.  When  discoverable  in  ordinary  thin- 
film  preparations,  the  parasites  may  number  anything  from 
50  per  c.mm.,  or  less,  to  200,000  per  c.mm.,  or  more.  In  the 
latter  case  there  will  be  200,000,000  parasites  per  c.cm.,  so 
that  if  I  c.cm.  or  more  of  such  blood  is  injected,  the  subject 
should  receive  enough  parasites  to  produce  fever  at  once  (by 


98  THE   PARASITIC    INVASION    IN    MAN  [Sect. 

hypothesis)  in  a  non-immune  person ;  and  this  has  almost 
occurred  in  some  of  the  cases.  But,  besides  the  number  of 
parasites  contained  in  the  inoculated  blood,  there  is  another 
question  requiring  consideration ;  that  is,  whether  many  of 
them  are  not  killed  in  the  syringe.  In  spite  of  the  experi- 
ments of  Bein  and  Sacharoff  (18-21  and  24),  I  think  that  this 
is  possible,  or  even  likely.  The  experiments  of  Celli  and 
Santori  (35-40),  in  which  various  sera  were  mixed  with  the 
inoculated  blood,  generally  show  long  incubation  periods, 
probably  due  to  such  destruction  of  the  parasites.  It  is  un- 
fortunate that  the  inoculated  parasites  have  not  been  counted 
in  a  single  one  of  these  experiments. 

We  need  not  refer  here  to  incubation  periods  determined 
by  observation  of  natural  infections. 

19.  The   Further   Progrress  of  the  Invasion. — We    now 

endeavour  to  trace  the  progress  of  the  invasion  after  the 
commencement  of  the  fever. 

(i).  Increase  of  the  parasites. — In  assuming  that  about  fifty 
Plasmodia  per  c.mm.  are  required  to  produce  the  first  illness, 
we  must  remember  that  this  applies  only  to  a  single  set  of 
parasites.  If  the  patient  contains  several  sets,  each  sporulating 
on  different  days,  the  total  number  of  plasmodia  should  by 
hypothesis  be  several  times  larger.  Moreover,  it  does  not 
follow,  if  fifty  Plasmodia  per  c.mm.  are  sufficient  to  produce 
the  first  attack,  that  they  will  suffice  to  cause  subsequent 
ones  after  the  patient  has  become  (hypothetically)  habituated 
to  their  poison.  Lastly,  the  various  species  may  vary  in 
"  virulence." 

As  I  have  said,  this  number,  which  may  be  called  the 
pyrogenous  limit,  is  merely  a  rough  estimate  of  mine.  Long 
researches  are  required  to  obtain  a  more  exact  figure  from 
observation,  but  it  may  be  useful  to  give  a  few  of  the  first 
counts  made  by  D.  Thomson  and  myself  in  cases  in  Liverpool, 
that  is,  not  in  fresh  infections  : — 


19] 


PROGRESS   OF  THE    INVASION 


99 


Case. 

Date. 

I. 

Quartan 

24.1. 1910 

M 

25.I.1910 

5) 

26.1. 1910 
27.1. 1910 

3, 

Malignant 

10.I.1910 

3- 

Malignant 

1 1.1.1910 

4- 

Malignant 

II.I.1910 

5- 

Malignant 

13.I.1910 

Temperature. 


397  C.  =  27  P.i 
slight  rigor  (?  temp.) 
37-40.  slight  rigor  =  4  P. 
normal  =  0  P. 
396  C.  =  26  P, 
4ro  C.  =  4o  P. 
38oC.  =  io  P. 
3870.  =  17  P. 


Parasites  per  c.mm. 


1,500,  mature 
83,  mature 
150,  mature 
36,  mature 
58,000,  young  forms 
300,000,  young  forms 
15,000,  young  forms 
55,000,  young  forms 


In  the  malignant  cases,  the  young  forms,  being  merely  the 
offspring  of  the  mature  parasites  which  caused  the  corresponding 
forms  and  which  were  at  the  time  in  the  inner  organs,  do  not 
give  the  number  of  the  parent  forms  ;  but  we  may  form  a 
rough  estimate  of  the  latter  by  dividing  the  number  of  young 
forms  by  ten.  The  quartan  case  (triple)  gives  some  justifica- 
tion for  the  figure  which  I  have  tentatively  selected  as  the 
pyrogenous  limit  (addendum   i). 

From  this  point,  to  judge  from  the  experimental  inoculations 
and  also  from  general  clinical  experience,  the  progress  of  an 
untreated  case  is  generally  that  the  parasites  continue  to 
increase  in  numbers  till  they  may  reach  the  figure  of  several 
hundred  thousands  per  c.mm. 

No  accurate  computations  of  the  increase  of  the  parasites 
seem  to  have  been  attempted  even  where  their  numbers  are 
large  enough  for  easy  enumeration.  If  they  increase  by  10 
at  each  generation,  they  should  multiply  from  50  to  5,000  in  four 
days  for  tertian  parasites,  but  there  is  reason  to  suppose  that 
the  increase  now  begins  to  be  considerably  checked. 

(2).  The  viaxinmin  number  of  parasites. — I  do  not  consider 
that  200,000  young  malignant  parasites  per  c.mm.  is  exception- 
ally high.  In  Mauritius  we  found  in  a  fatal  case  12/100  of  the 
haematids  infected.      Several  authors  record  30/100,  and  Rogers 

^  Here  P.  stands  for  the  Pyretic  Scale  which  I  propose  for  pathological  work.     It 
is  merely  the  Centigrade  Scale  between  37°  and  47°  divided  into  100  parts.     Thus  : — 
0°  P.  =37°  C.  =98 '6°  F.  =29 '6°  R.  =  normal  human   blood  temperature 
30°  P.  =40°  C.  =  104°  F.  =32°  R.  =high  fever. 


loo  THE   PARASITIC    INVASION    IN    MAN  [Sect. 

[1908,  p.  222]  mentions  a  fatal  case  "  with  more  parasites  than 
corpuscles."  Three  or  four  parasites  are  frequently  found  in 
one  haematid.  Similar  copious  infections  are  the  rule  in  genus 
Haemoproteiis  {Halteridium)  of  birds. 

There  are  innumerable  references  to  this  part  of  the  subject 
in  the  literature,  but  none  of  them  are  exact.  Many  authors 
give  the  proportion  of  their  cases  in  which  they  have  detected 
the  Plasmodia  in  a  single  thin-film  specimen — that  is,  I  suppose, 
in  numbers  over  about  50  per  c.mm.  Rogers  states  that  out 
of  his  successful  cases  they  were  detected  in  a  minute  or  two  in 
78%  and  in  over  five  minutes  in  10%  [1908,  p.  220]  ;  but  he 
failed  to  find  any  parasites  in  10-20%  of  undoubted  malaria 
cases.  Other  observers  have  had  still  more  failures.  In  Liver- 
pool we  nearly  always  succeed  if  fever  is  present,  but  the 
blood  is  generally  distributed  to  a  class.  It  is  obviously  a 
question  not  only  of  the  number  of  parasites,  but  of  skill ;  and 
I  should  add  that  not  all  of  those  who  write  on  the  subject  are 
as  expert  as  may  be  imagined. 

According  to  the  classical  theorem  of  Marchiafava,  Celli  and 
Bio-nami,  the  sporids  of  P.  falciparum  tend  to  retire  to  the  inner 
organs  after  reaching  a  certain  size.  I  remember  a  case  where 
I  undertook  to  demonstrate  the  plasmodia  to  a  sceptic,  and 
found  for  the  purpose  a  case  swarming  with  young  malignant 
parasites.  A  few  hours  later,  however,  when  the  sceptic  saw 
the  case,  they  had  all  vanished !  Nevertheless,  I  think  that 
this  theorem  requires  to  be  better  verified  by  strict  numerical 
work,  as  it  is  possible  that  much  of  this  supposed  disappearance 
from  the  peripheral  circulation  is  due  to  the  death  of  the 
organisms  (addendum  i). 

(3).  Limiiatien  -of  the  invasion. —  Clearly,  if  the  parasites 
can  continue  to  multiply  for  ever  "aT  the  original  rate,  every 
untreated  case  would  infallibly  die.  We  are  therefore  obliged 
to  admit  that  something  happens  to  check  the  invasion.  The 
subject  belongs  to  the  pathology  of  malaria,  but  we  should  note 
the  following  points. 


19]  PROGRESS   OF   THE    INVASION  loi 

The  arrest  of  the  invasion  may  be  due  to  one  or  both  of  two 
causes.  Either  the  parasites  themselves  begin  to  lose  their 
power  of  reproduction,  or  else  they  or  the  body  produce  some- 
thing which  opposes  them.  I  doubt  the  former  hypothesis, 
because  the  same  number  of  spores  appear  still  to  be  formed  ; 
because  the  parasites  do  continue  to  reproduce  in  smaller 
numbers  for  months,  or  even  years  ;  and  because  in  some  cases 
they  actually  do  continue  multiplying  until  they  kill  the  patient. 
Whether  they  are  destroyed  by  their  own  toxins,  or  by  some 
germicidal  substance  produced  by  the  host,  is  a  question  which 
deserves  much  more  attention  than  it  has  received.  The  idea 
that  they  are  destroyed  solely  by  the  phagocytes  is  no  longer 
generally  accepted. 

Whatever  it  is,  the  germicidal  substance  appears  usually  to 
increase  in  power  with  the  number  of  the  parasites,  and  there- 
fore to  check  the  invasion  at  its  height.  On  the  other  hand, 
the  failure  of  many  inoculation  experiments  suggests  that  some 
persons  possess  such  a  substance  from  the  first — unless  the 
failures  have  been  due  to  some  unseen  error.  Out  of  six 
birds  which  escaped  infection  in  my  mosquito  inoculations, 
one  (the  only  survivor)  was  infected  on  a  second  trial  ;  and 
the  same  thing  happened  in  some  of  the  human  experiments. 

The  literature  contains  many  references  to  the  sudden 
disappearance  of  a  whole  generation  of  plasmodia  —  not  in 
consequence  of  quinine,  but  frequently  following  rest  in  bed, 
good  food  or  shelter  from  heat.  In  the  quartan  case  mentioned 
in  subsection  (i),  a  large  brood  followed  the  sporulation  of 
24th  January,  but  of  these,  without  quinine,  only  about  36 
per  c.mm.  reached  maturity  three  days  later.  Many  observers 
describe  the  appearance  of  death — loss  or  change  of  staining 
capacity,  and  so  on — among  the  parasites  on  such  occasions. 

(4).  TJie  illness  is  due  to  a  toxin. — This  point  also  belongs  to 
the  pathological  side  of  the  subject.  Omitting  reference  to  the 
older  hypotheses,  it  is  now  almost  certain  that  the  patient's 
fever  is  connected  with  the  discharge  of  some  toxic  substance 


I02  THE   PARASITIC    INVASION    IN    MAN  [Sect. 

from  each  mature  sporid  at  the  moment  when  its  spores  are 
scattered  in  the  serum.  Some  of  the  older  inoculation  experi- 
ments made  with  blood  taken  from  a  source  in  the  state  of 
rigor — that  is,  at  the  moment  when  the  sporids  are  breaking 
up — were  followed  by  an  immediate  slight  reaction,  suggesting 
that  that  blood  contained  a  toxin  as  well  as  parasites.  These 
results  are,  however,  scarcely  definite  enough  to  prove  the  point, 
especially  as  the  inoculation  of  healthy  blood  is  sometimes 
followed  by  such  a  reaction.  But  the  following  excellent 
experiments  of  Rosenau,  Parker,  Francis  and  Beyer  [1905]  were 
much  more  decisive. 

Case  I.  At  Vera  Cruz,  Mexico,  at  noon  on  27th  October 
1903,  100  c.cm.  of  blood  were  drawn  from  F.  Martinez,  suffer- 
ing from  a  declining  paroxysm  of  P.  falciparum  ;  temperature 
38"2°  C.  (=12  P.);  parasites,  young  sporids  and  also  gametids. 
The  serum  of  this  blood  was  separated,  diluted  with  an  equal 
part  of  salt  solution,  passed  through  a  Chamberland  B.  filter 
(tested),  and  injected  (20  c.cm.)  into  J.  Ojeira,  and  (equivalent) 
into  L.  Peredo.     Neither  subject  showed  any  symptom. 

Case  2.  At  the  same  place,  at  12.30  on  6th  November  1903, 
A.  Mendez  was  suffering  from  a  severe  benign-tertian  rigor 
(double  infection) ;  temperature  39*1°  C.  (21  P.),  rising  to  40*2°  C. 
(32  P.).  At  that  moment  125  c.cm.  of  his  blood  were  drawn 
and  defibrinated.  To  25  c.cm.  the  same  quantity  of  salt 
solution  was  added,  and  the  mixture  was  passed  through  the 
same  filter.  The  filtrate  had  no  figured  elements,  but  showed 
a  red  tinge,  and  9  c.cm.  of  it  were  injected  at  1.40  r.M.  into 
the  right  basilic  vein  of  L.  Peredo.  Thirty-five  minutes  later 
the  subject  "  began  having  chilly  sensations  and  headaches, 
and  presently  went  to  bed  covering  himself  with  his  blanket 
(2.25  P.M.),  Five  minutes  later  (2.30)  he  was  having  a  violent 
chill,  his  teeth  chattering  so  that  we  could  not  trust  the 
thermometer  in  his  mouth."  Patient  was  pale  and  vomited. 
Chill  lasted   to  3.15   p.m.;    vomited  again  at  3.30;    fever  rose 


19]  PROGRESS   OF   THE    INVASION  103 

rapidly  to  387°  C.  (17  P.)  at  4  p.m.,  nearly  normal  at  10.30  P.M. 
Authors  put  the  duration  of  the  paroxysm  at  about  eight  hours. 

Case  3.  At  same  place  and  date,  at  2  P.M.,  2  c.cm.  of  the 
same  blood  of  A.  Mendez,  mixed  with  an  equal  volume  of  salt 
solution,  but  unfiltered,  were  injected  intravenously  into  J. 
Ojeira.  Subject  "  reacted  within  an  hour,  with  a  slight  rise 
of  temperature  and  nausea,  and  four  days  afterwards  developed 
a  typical  malarial  paroxysm,  with  many  tertian  parasites  in 
his  peripheral  blood."  Typical  fever  (double  infection)  with 
a  few  parasites  at  7  A.M.  on  loth  November.  (Case  51  of 
section  14.)  In  this  case  the  preliminary  rise  of  temperature, 
which  began  within  an  hour  after  injection,  reached  37'9°  C. 
(9  P.)  and  lasted  five  hours. 

Thus,  both  the  subjects  inoculated  with  the  blood  of  Mendez 
taken  during  rigor  had  attacks  of  fever  similar  to  that  of  the 
source ;  but  the  first  subject  inoculated  with  filtered  blood  did 
not  become  infected,  while  the  second  subject  inoculated  with 
unfiltered  blood  became  infected  with  the  same  parasites  as  in 
the  source. 

Unfortunately,  no  estimate  is  given  of  the  number  of  parasites 
in  the  inoculated  blood.  The  infection  of  Mendez  was,  however, 
said  to  be  "heavy" — let  us  suppose  10,000  parasites  per  c.mm. 
We  may  thus  calculate  : — 

The  toxin  of  45,000,000  benign  tertian  parasites  in  4*5  c.cm. 
of  blood  caused  eight  hours'  fever,  reaching  to  387''  C.  (17  P.) 
in   Peredo. 

The  toxin  of  20,000,000  of  the  same  parasites  in  2  c.cm.  of 
blood  caused  five  hours'  fever,  reaching  to  37*9°  C.  (9  P.)  in  Ojeira. 

The  corresponding  ratios,  namely,  4'5/2"o,  8/5,  17/9  (taking 
o  P.  as  the  normal  temperature),  are  not  dissimilar.  The  pyro- 
genous  limit  here  suggested  is  lower  than  my  arbitrary  figure 
of  150,000,000;  but  I  may  have  underestimated  the  infection 
of  Mendez,  and  the  weights  of  the  subjects  are  not  recorded. 


I04  THE    PARASITIC    INVASION    IN    MAN  [Sect. 

The  corresponding  paroxyzm  of  Mendez  himself  rose  to 
40'i'  C.  and  lasted  five  hours  ;  but  his  was  an  old  case,  and 
cannot  be  compared  with  the  others. 

We  do  not  know  the  nature  of  the  toxin,  but  I  have  always 

thought  it  likely  to  be  some  soluble  constituent  of  the  plasmodin. 

It  is  generally  supposed  that  the  various  species  of  plasmodia 

produce   toxins   of  different   strength   (or   virulence) ;   but   we 

should  await  better  proof  of  this. 

(5).  Antitoxins. — Just  as  the  body  certainly  produces  some 
germicidal  property  capable  of  limiting  the  number  of  the 
parasites,  so  it  must  certainly  produce  some  antitoxic 
property  capable  of  destroying,  or  at  least  eliminating,  their 
poison.  We  do  not  know  its  nature,  but  infer  for  the  follow- 
ing reasons  that  its  power  increases  with  time : — 

(i)  From  the  time  of  the  ancients  it  has  been  observed 
that  malarial  fever  begins  with  remittent  fever,  due 
to  the  overlapping  of  the  paroxysms,  and  ends  with 
intermittent  fever,  due  to  the  shortening  and  separa- 
tion  of  the   paroxysms.     This   shortening   of  each 
attack    of  fever   is   not   always   accompanied    by  a 
decrease   in    the    number   of    parasites,   and    must 
therefore  be  due  to  something  which  reduces  their 
effect  on  the  body. 
(2)   Old    cases,    especially    children,    often     scarcely    feel 
the  paroxysm,  although  considerable  fever  may  be 
present. 
I  have  observed  in  many  untreated  cases  that  the  number 
of  parasites  continues  to  increase,  although  each  attack  of  fever 
tends  to  become  more  and  more  mild.     This  suggests  that  the 
antitoxic  power  of  the  blood  tends  to  be  developed  sooner  than 
the  germicidal  power. 

20.  The  Decline  of  the  Invasion.— (i).  The  period  of  regular 
paroxysms. — It  is  not  easy  to  find  untreated  cases  for  study, 
but  from  such  as  I  have  been  able  to  examine  or  to  read  about. 


2o]  DECLINE   OF   THE    INVASION  105 

I  infer  (subject  to  correction  by  more  exact  numerical  methods) 
that  the  following  course  of  events  occurs  : — 

After  reaching  a  figure  of  say  50  or  500  per  c.mm.  the  parasites 
tend  to  increase  more  slowly  owing  to  the  increasing  germicidal 
power  of  the  blood.  That  is,  while  each  sporid  still  produces 
(?)  the  same  number  of  spores,  a  greater  and  greater  number  of 
the  young  parasites  are  killed ;  so  that  the  invasion  tends  to 
reach  a  limit  of  something  like  1,000  to  10,000  mature  sporids 
at  every  generation.  But  this  limit  may  not  be  reached  perhaps 
for  some  weeks. 

In  the  meantime  the  increasing  antitoxic  power  of  the  blood 
tends  to  shorten  each  paroxysm  more  and  more  ;  the  fever,  at 
first  remittent,  breaks  up  into  a  series  of  intermittent  attacks. 
Thus,  though  at  each  paroxysm  the  total  number  of  parasites 
may  be  slightly  increased  as  that  number  approaches  the  highest 
limit,  yet  the  parallel  increase  of  the  antitoxic  power  annuls 
the  effect  of  the  parasitic  increase,  so  that  the  patient  now 
often  suffers  from  a  long  series  of  paroxysms  of  almost  equal 
intensity,  which  give  the  typical  classical  picture  of  a  malarial 
fever. 

This  period  may  last,  I  think,  for  some  weeks,  but  of  course 
the  process  may  be  subject  to  modification.  Thus,  food  and 
rest  may  help  the  patient,  while  in  some  cases  death  may  occur 
in  spite  of  quinine  from  an  unlimited  propagation  of  the  parasites. 
Fortunately,  however,  the  period  ends  abruptly  in  most  cases 
even  without  quinine.  The  paroxysms  become  very  mild,  and 
then,  suddenly,  the  sporids  undergo  an  immense  fall  in  numbers  ; 
and  this  stage  of  the  disease  ends. 

The  collateral  incidents  and  symptoms  are  minutely  described 
in  pathological  books,  and  it  is  necessary  here  to  refer  only  to 
some  important  points. 

According  to  the  elementary  law  of  Golgi,  a  patient  may 
contain,  not  only  one  set  of  parasites  sporulating  every  second, 
or  every  third  day  (as  the  case  may  be),  but  two  or  three  sets 
sporulating  on  different  days.     He  may  also  contain   sets   of 


io6  THE   PARASITIC    INVASION    IN    MAN  [Sect. 

parasites  of  different  species.  The  rule  generally  accepted  is 
that  each  set  of  parasites  continues  its  own  evolution  independently 
of  other  sets  which  may  be  present.  But  much  more  precise 
work  requires  to  be  done  on  this  point,  and  on  the 
following : — 

{a)  The  exact  increase  of  severity,  if  any,  of  a  paroxysm 

due  to  the  simultaneous  sporulation  of  two  sets  of 

parasites  of  different  species  on  the  same  day. 
{b)  Does   one   set    of    parasites    affect   the   body-reactions 

against  another  set  of  the  same  or  of  a  different 

species  ? 
if)  Do  different  sets  of  the  same  species  tend  to  coalesce  ? 
{d)  Explanation  of  the  (apparent)  extinction   of  one  set 

long  before  that  of  another. 
The  presence  of  different  sets  may  obviously  be  ascribed  to 
inoculation  of  the  patient  on  different  dates.  This  matter  has 
already  been  touched  upon,  but  not  exhaustively,  in  some  of  the 
inoculation  experiments,  especially  in  those  of  Di  Mattei,  Elting 
and  Jancso. 

Besides  fever,  the  parasites  produce  anaemia.  This  has  often 
been  measured  absolutely,  but  never  exactly  in  correlation  with 
the  number  of  parasites.  It  is  supposed  that  the  toxin  of  the 
Plasmodia  destroys  many  of  the  haematids  which  are  not 
mechanically  broken  up  by  the  parasites  themselves.  More 
exact  researches  are  also  required  regarding  the  absolute  and 
relative  leiicocytic  variations  in  correlation  with  the  number  of 
Plasmodia. 

The  different  species  produce  paroxysms  of  somewhat 
different  type  and  intensity.  Many  authors  quote  figures,  but 
without  correlation  with  the  number  of  parasites.  Thayer  and 
Hewetson  [1895]  give  i  r8  hours  as  the  average  duration  of  the 
single  benign  tertian  paroxysm,  about  ten  hours  as  that  of 
quartan  paroxysms,  and  twenty  to  twenty-one  hours  as  that 
of  the  malignant  paroxysms.  The  massing  of  the  malignant 
parasites    in   the    inner    organs,   and    many   other   details,   are 


2o]  ONSET   OF   SEXUAL   FORMS  107 

pathological  matters.     The  enlargement  of  the  spleen  and  liver 
will  be  dealt  with  in  section  22. 

(2).  The  appearance  of  sexual  forms. — With  the  quartan  and 
benign  tertian  parasites,  these  forms  begin  to  be  seen  very 
early  after  the  plasmodia  become  numerous  enough  to  be 
found  at  all.  It  is  very  doubtful  whether  they  are  or  are  not 
produced  in  broods  at  any  given  moment  during  the  course 
of  the  invasion  or  during  the  development  of  a  single  genera- 
tion ;  and  still  more  doubtful  how  long  a  single  gametid  can 
live  in  the  blood  of  the  patient.  The  opinions  of  many 
writers  may  be  quoted,  but,  unfortunately,  they  are  only 
opinions.  Schaudinn's  case  will  be  referred  to  presently. 
The  malignant  gametids  are  much  more  easy  to  study.  They 
begin  to  appear  about  a  week  after  the  onset  of  the  fever  and 
may  remain  circulating  in  the  blood  for  several  weeks.  We 
do  not  know  what  determines  their  appearance,  but  the  asexual 
forms  and  the  fever  frequently  vanish  when  they  appear  (which 
may  often  be  due  to  the  fact  that  quinine  influences  the  sporids 
more  than  it  affects  the  crescents).  In  untreated  cases,  how- 
ever, we  may  often  find  both  forms  together  for  many  days, 
though  the  sporids  are  apt  to  be  scanty.  In  such  cases  there 
may  be  slight  oscillations  of  temperature,  which  some  writers 
have  attributed  to  the  crescents.  Often,  also,  the  sporids  may 
be  still  present  in  large  numbers  though  they  are  too  few  to 
be  detected.  In  infected  sailors  in  Liverpool  we  often  find 
crescents  with  great  certainty,  unless  the  earlier  infection  is 
cut  short  with  quinine.  But  many  writers  complain  that  in 
certain  localities  they  cannot  find  them  as  frequently  as  might 
be  expected,  and  I  have  had  the  same  experience  in  India  and 
West  Africa.  To  explain  such  cases  I  have  surmised  that  the 
production  of  sexual  forms  may  be  largely  influenced  by  season 
— that  they  may  be  produced  abundantly  for  a  few  weeks,  but 
only  at  that  time  of  year  when  the  local  carrying  Anophe- 
lines  are  most  abundant.  Caccini  [1902]  says  that  several 
observers  have  noted  the  absence  of  crescents  when  the  new 


io8  THE   PARASITIC    INVASION    IN    MAN  [Sect. 

malaria  season  is  imminent,  and  that  he  himself  has  never 
found  crescents  in  Italy  from  April  to  June.  For  another 
example,  I  found  very  few  crescents  at  the  foot  of  the 
Darjeeling  mountains  in  1898  at  a  place  where  they  had 
been  frequently  seen  by  another  observer  a  few  months  earlier. 
But  this  is  a  mere  conjecture,  and  one  which  requires  long 
study  for  verification  ;  and  it  scarcely  explains  why  sailors 
in  Liverpool  have  crescents  so  regularly.  The  early  use  of 
quinine — to  which  sailors  are  not  addicted — may  also  explain 
the  paucity  of  crescents  in  many  cases.  Lastly,  it  is  possible 
that  the  sexual  forms  are  produced  only  during  the  earlier 
stages  of  an  infection — that  in  an  old  infection,  when,  so  to 
speak,  parasites  become  worn  out,  they  no  longer  produce 
sexual  forms,  just  as  the  oldest  broods  of  human  cells  fail  to 
produce  them.  In  my  experience  crescents  are  common  during 
the  first  few  months  of  an  infection,  but  comparatively  rare  at 
later  stages.  Failure  to  find  "  flagellated  forms  "  (spermatophoria) 
must  be  generally  due  to  faulty  technics. 

(3).  The  period  of  rallies  and  relapses. — We  have  seen  then 
that  the  period  of  regularly  repeated  paroxysms  generally  ends 
after  a  few  weeks,  even  without  treatment,  in  a  great  decline 
in  the  number  of  sporids.  The  gametids,  especially  the 
crescents,  may  still  remain  numerous,  but  the  asexual  forms 
which  cause  the  illness  diminish  so  much  that  they  fall  below 
the  pyrogenous  limit  and  cannot  easily  be  found. 

The  patient  now  improves  in  health.  His  paroxysms 
cease,  his  haematids  increase,  his  spleen  diminishes,  and  he 
begins  to  gain  flesh  again.     I  call  this  the  rally. 

From  this  point  two  things  may  happen.  The  patient  may 
recover  completely,  or — without  reinfection — he  may  suddenly 
suffer  from  a  relapse. 

In  the  relapse  all  the  old  symptoms  of  the  period  of 
regular  paroxysms,  sometimes  less  in  intensity  and  sometimes 
worse,  recur.  The  fever  may  recommence  with  the  remittent 
form,   and    may    then,    as    before,   become    intermittent.     The 


2o]  RALLIES   AND   RELAPSES  109 

anaemia  and  the  splenomegaly — not  yet  completely  recovered 
from  since  the  first  attack — will  again  increase,  and  to  a  greater 
degree  than  at  first.  Large  numbers  of  sporids  will  again  be 
found  in  the  blood,  and  may  be  followed  as  before  by  crops 
of  gametids.  Finally,  in  most  cases,  even  when  untreated, 
recovery,  accompanied  by  a  great  decrease  of  sporids,  will 
occur  again. 

This  is  followed  by  another  rally,  which  in  its  turn  7nay  be 
followed  by  another  relapse — and  so  on,  indefinitely,  for  months 
or  perhaps  years. 

Such,  in  my  opinion,  is  the  normal  course  of  malaria,  whether 
untreated  or  badly  treated.  But  as  the  former  kind  of  case 
can  scarcely  ever  be  observed,  my  opinion  is  based,  not  upon 
continuous  observation  of  many  cases,  but  upon  correlation  of 
different  periods  in  different  cases.  I  think,  however,  that  most 
students  of  tropical  malaria  share  that  opinion. 

During  the  whole  of  this  period  the  emaciation,  anaemia, 
splenomegaly  and  secondary  symptoms  tend  to  increase  with 
each  relapse  and  to  diminish  with  each  rally.  But  the  increase 
seems  at  first  to  be  generally  greater  than  the  decrease,  though 
by  a  diminishing  increment.  Thus,  after  some  months  the 
patient  tends  to  reach  a  condition  in  which  these  symptoms 
arrive  at  something  like  a  fixed  limit — considerable  emaciation, 
anaemia,  splenomegaly,  oedema,  dyspepsia,  etc.  This  condi- 
tion is  well  known  as  that  of  chronic  malaria,  and  is  only  too 
frequently  seen  in  malarious  places,  especially  among  children. 

In  most  cases,  especially  in  children,  after  the  fixed  limit 
has  been  reached  a  general  improvement  sets  in.  After  all, 
the  disease  is  essentially  a  benign  one.  Each  relapse  now 
affects  the  patient  less  and  less,  and  the  secondary  symptoms 
begin  to  decrease  more  with  each  rally  than  they  increase  with 
each  relapse.  After  an  unknown  average  duration,  complete 
recovery  certainly  occurs  in  the  large  majority  of  cases,  without 
any  serious  treatment.  Such  cases  are  said  to  have  become 
partially  immune. 


no  THE   PARASITIC    INVASION    IN   MAN  [Sect. 

On  the  other  hand,  deatJi  occurs  in  many  as  the  result  of 
"  pernicious  paroxysms,"  intercurrent  affections  such  as  dysentery 
and  pneumonia,  or  general  weakness  assisted  by  poverty  caused 
by  inability  to  work. 

Of  course  this  picture — or  rather  sketch — is  modified  by 
many  conditions.  Patients  who  have  already  become  partially 
immune  during  childhood  or  after  many  attacks,  suffer  much 
less  on  reinfection ;  and  good  food  and  change  of  climate 
benefit  the  case,  while  complications  such  as  dysentery,  sprue 
and  ankylostomiasis,  have  the  opposite  effect.  The  most  usual 
modification  is  that  caused  by  inadequate  treatment,  and  I 
continue  to  see  many  such  cases  in  Liverpool.  The  history 
is  always  the  same.  The  patient  has  been  instructed  to  take 
quinine  during  his  attack,  and  for  a  week  or  two  afterwards. 
This  is  insufficient,  and  the  inevitable  relapse  occurs.  But 
the  patient  seldom  falls  into  the  extreme  condition  of  wholly 
untreated  cases.  The  drug  has  not  extirpated  the  infection, 
but  it  has  checked  each  relapse  as  it  occurs,  and  has  controlled 
the  anaemia  and  splenomegaly.  Such  especially  is  the  condition 
of  the  infected  sailors  of  whom  we  see  so  many  in  Liverpool. 
They  still  have  relapses,  but  the  spleen  is  not  markedly  enlarged 
and  the  anaemia  not  very  pronounced. 

Works  written  on  malaria  in  temperate  and  often  more 
civilised  countries  do  not  always  give  a  complete  picture  of 
the  disease  as  it  occurs  among  poor  natives  in  the  tropics. 
This  is  due  to  the  fact  that  the  more  general  use  of  quinine 
in  the  former  tends  to  abbreviate  the  course  of  the  infection. 
On  the  other  hand,  the  great  majority  of  cases  in  the  countless 
malarious  villages  of  the  tropics  are  cases  of  chronic  malaria 
— untreated,  subject  to  frequent  reinfections,  and  with  anaemia, 
enlargement  of  the  spleen  and  numerous  relapses.  In  temperate 
climates,  our  cases  are  mostly  in  the  early  period  of  regular 
paroxysms ;  in  the  tropics  they  are  mostly  in  the  long-continued 
period  of  rallies  and  relapses. 

(4).   The  parasites  during  the  rallies. — The  general  observa- 


2o]  THE    PARASITES    DURING   THE   RALLIES  iii 

tion  that  the  degree  of  fever  depends  ceteris  paribus  upon  the 
number  of  parasites  suggests  that  when  there  is  no  fever  the 
parasites  are  likely  to  be  at  least  scanty.  Hence,  as  is  to  be 
expected,  in  the  rallies  between  relapses  few  sporids,  and  indeed 
very  often  none  at  all,  can  be  discovered  in  the  small  quantities 
of  blood  examined  under  the  microscope — though,  of  course, 
the  gametids  (which  do  not  seem  to  produce  fever)  may  still 
abound.  Nevertheless,  when  the  relapse  occurs,  the  sporids 
again  appear  in  detectable  or  large  numbers.  What  happens 
to  them  when  they  disappear  and  reappear  in  this  manner  ? 

We  can  easily  observe  that  the  number  of  parasites,  when 
they  are  numerous  enough  to  be  found,  often  varies  largely. 
It  is  therefore  equally  easy  to  infer  that  when  we  can  no  longer 
find  them,  this  is  due  simply  to  the  fact  that  they  have  become 
too  scarce  to  be  found.  But  many  writers  seem  to  think  that 
when  they  cannot  find  sporids  none  exist,  and  have  therefore 
sought  other  explanations  of  the  disappearance  and  reappear- 
ance referred  to. 

Years  ago  Marchiafava  and  Bignami  suggested  that  when 
they  disappear  for  long  periods  the  parasites  may  become 
encysted  somewhere  in  the  inner  organs ;  or  that  they  may 
die  out  altogether,  and  that  the  relapse  may  be  caused  by 
spores  which  escape  from  phagocytes  in  which  they  have  been 
living  in  a  dormant  condition.  No  evidence  has  been  given 
for  these  views  ;  yet  it  should  be  easy  to  obtain  in  the  malaria 
of  birds,  which  remain  infected  for  months.  In  1898  I  examined 
many  birds  in  vain  for  the  supposed  encysted  forms. 

Golgi,  Mannaberg  and  others  thought  that  crescents  keep 
the  infection  alive  during  the  rallies.  Thus  Mannaberg  said 
[1894,  p.  302]:  "These  relapses  in  localities  free  from  malaria 
are  to  be  explained  only  by  the  persistence  of  parasites 
possessing  certain  powers  of  resistance  (probably  the  crescentic 
bodies)  within  certain  tissues."  But  why  are  any  special  powers 
of  resistance  required ;  and  how  explain  relapses  with  the 
parasites   which   do    not    produce   crescents  ?      Many   authors. 


112  THE   PARASITIC    INVASION    IN    MAN  [Sect. 

working,  I  believe,  with  unstained  films,  have  described  and 
figured  sporulation  of  crescents ;  but  others  attributed  this 
merely  to  post-mortem  vacuolisation.  We  have  never  found 
sporulating  crescents  in  stained  films  in  Liverpool,  though 
numbers  of  these  bodies  are  examined  in  class.  B,  Grassi 
[1901]  suggested  that  the  relapses  are  caused  by  parthenogenetic 
reproduction  in  the  gametids. 

This  idea  was  followed  up  by  F.  Schaudinn  [1903].  A 
patient  who  had  suffered  long  from  P.  vivax  was  attacked  on 
29th  April  and  ist  May,  and  was  found  to  contain  both  sporids 
and  gametids.  A  rally  now  occurred,  during  which  daily 
examination  disclosed  varying  numbers  of  gametids  only.  On 
25th  May  these  parasites  were  more  plentiful.  Next  day  curious 
changes  were  noted  in  the  female  gametids,  suggesting  that  they 
were  producing  spores  similar  to  those  ordinarily  produced  by 
the  asexual  sporids.  The  author  considered  this  to  have 
occurred  independently  of  fertilisation  by  the  male  gametids, 
and  to  be  due  to  parthenogenesis.  The  same  day  (26th  May) 
the  patient  had  a  slight  rise  of  temperature  to  38*4°  C,  and  in 
the  evening  ordinary  young  sporids  were  found.  Next  day  only 
these  forms  occurred.  On  28th  May  there  was  a  typical  attack 
with  temperature  reaching  4075°  C,  and  with  the  usual  sporids. 
Next  day  only  gametids  were  again  found.  The  author  care- 
fully described  the  parthenogenetic  forms  and  traced  the 
corresponding  changes  in  the  nucleus. 

These  observations  were  hailed  as  an  important  discovery  by 
many  writers,  especially  zoologists.  They  have  been  partially 
repeated  by  Maurer  [1902],  Bluml  and  Merz  [1908],  Harrison 
[1909]  and  others  ;  and  many  of  the  younger  and  more  confident 
workers  have  spent  much  time  in  attempts  to  verify  them,  or 
have  seen  objects  like  those  described  by  Schaudinn.  But  the 
objects  twice  seen  by  Maurer  are  not  in  any  way  proved  to  be 
parthenogenetic  forms  ;  while  those  observed  in  six  preparations 
by  Bluml  and  Merz  are  supposed  by  the  authors  to  be  more 
probably  cases  of  production  of  gametids  by  gametids — another 


2o]  THE   PARASITES    DURING   THE   RALLIES  113 

hypothesis ;  and  these  authors  do  not  agree  with  Maurer. 
Harrison  admits  that  the  supposod  "  gametoschizonts "  seen 
by  him  may  be  merely  double  infections  of  haematids  by  a 
gametid  and  a  sporid.  Craig  [igo6]  thinks  that "  intracorpuscular 
conjugation  "  may  maintain  the  infection. 

It  is  easy  to  see  under  the  microscope  objects  which  suggest 
this  or  that  hypothesis,  but  only  the  most  patient  and  long- 
continued  labours  suffice  to  prove  the  truth.  Schaudinn's  case 
seems  to  me  of  doubtful  value.  I  note  especially  that  between 
1st  and  25th  May  the  number  of  gametids  varied,  and  was 
increased  on  the  latter  date.  But  this  variation  suggests  that 
they  were  being  produced  all  the  time.  The  gametids  are 
supposed  to  be  produced  from  ordinary  spores ;  so  that  we 
are  forced  to  infer  that  a  number  of  sporids,  some  of  them 
generating  gametids,  were  present  in  the  patient's  body,  although 
they  were  too  few  to  be  detected  in  the  small  quantities  of  blood 
examined  by  the  author.  On  25th  May  they  probably  increased 
in  number  sufficiently  to  induce  a  slight  attack  of  fever,  and 
were  then  mistaken  for  parthenogenetic  gametids.  On  28th 
May  they  produced  a  typical  attack  ;  and  that  is  all.  The 
supposed  nuclear  changes  were  reported  on  evidence  of  no  great 
value.  The  cells  were  not  actually  observed  undergoing  the 
development  which  the  author  describes.  He  merely  inferred 
the  existence  of  the  development  from  a  study  of  different  cells 
in  what  he  thought  were  different  stages  of  that  development. 
Worst  of  all,  no  numerical  estimates  are  given.  The  same 
author  enunciated  many  other  hypotheses  on  similar  evidence. 
I  doubt  whether  parthenogenesis  occurs  with  the  parasites  of 
malaria,  for  the  following  reasons  : — 

{a)  If  it  occurs  in  one  species  it  ought  to  occur  in  all.  It 
ought  therefore  to  be  easily  observed  in  birds' 
malaria,  and  in  crescents.  I  have  been  examining 
the  latter  for  fifteen  years  and  have  never  seen  in 
them  anything  suggesting  parthenogenesis.  Yet  they 
possess  a  definite  and  uniform  outline  which  should 

H 


ii4  THE   PARASITIC    INVASION    IN    MAN  [Sect. 

be   much    modified    by   such    cellular    changes   as 
Schaudinn  described.     A.    Carducci  [1905],  though 
favourably    inclined    towards     the    parthenogenetic 
speculation,  failed    after   careful    search    in    finding 
any  evidence  of  it  in  crescents.^ 
{b)  I  have  frequently  seen  relapses  occur  in  cases   of  P. 
falciparum  in  which    no    crescents   at   all  could  be 
found,     Carducci  notes  the  same  (see  section  65). 
{c)  In    four   experiments   (see   end    of  section    14)   blood 
containing   numerous    crescents   only   was   injected 
into  healthy  persons  by  capable  observers  without 
producing   any  infection  whatever.     Yet   I   showed 
in  1 895- 1 896  that  crescents  live  on  ice  and  for  hours 
under  vaseline.     Why  then,  if  Schaudinn's  hypothesis 
is  true,  did  they  not  infect  any  of  these  four  persons  ? 
{d)  If  relapses  are  caused  merely  by  some  natural  develop- 
ment in  the    parasites  we   should  expect   them    to 
occur  more  or   less    independently  of  the  state  of 
health  of  the  host — which  does  not  seem  to  be  the 
case  (see  subsection  6). 
{e)   If  it  occurs  at  all,  parthenogenesis  ought  to  be  common 
enough  to  be  demonstrable  with  ease  and  certainty. 
This  subject  is  of  great  importance  in  connection  with  the 
prevention  of  malaria.     Crescents  withstand  much  medication 
with  quinine,  and  if  they  keep  the  infection  alive  in  patients,  it 
follows  that  quinine  loses   much  of  its  value  as  a  public  pro- 
phylactic against  malaria.    But,  while  I  am  quite  ready  to  accept 
any  evidence  for  it  which  may  be  offered,  at  present  I  do  not 
think  that  the  Grassi  -  Schaudinn  speculation   is   even  nearly 
proved. 

The  fact  that  the  parasites  disappear  at  each  rally  and  re- 
appear at  each  relapse  is  explained  quite  easily  and  sufficiently. 
In  the  rallies  they  become  too  few  to  cause  fever  or  to  be 

^  H.  M.  Neeb  [1909]  in  a  paper  just  to  hand  shows  careful,  but  I  think  still  quite 
inconclusive,  work  in  favour  of  parthenogenesis  in  crescents. 


2o]  THE   PARASITES    DURING   THE    RALLIES  115 

detectable  in  the  small  quantities  of  blood  examined  ;  in  the 
relapses  they  become  numerous  again,  I  cannot  see  that  a 
simpler  or  more  satisfactory  explanation  is  required.  We 
observe  the  same  process  in  relapsing  fever,  tuberculosis, 
trypanosomiasis  and  other  diseases. 

A  good  writer  once  said :  "  It  is  hardly  conceivable  that  it 
(the  parasite)  should  remain  in  the  general  circulation,  passing 
through  its  ordinary  cycle  of  existence,  without  causing  any 
symptoms  whatever.  Further,  the  failure  of  repeated  examina- 
tions of  the  blood  of  patients  who  have  previously  suffered 
from  malaria  to  reveal  the  presence  of  the  parasite  renders 
this  most  unlikely."  It  is  impossible  to  accept  such  a  train 
of  thought.  If  150,000,000  sporids  cause  but  little  fever  in  a 
man  of  medium  weight,  1,000  or  100  should  cause  none  at  all, 
and  yet  will  be  quite  sufficient  to  keep  the  infection  alive  in 
him.  But  if  the  parasites  are  so  few,  what  chance  has  the 
medical  man  of  finding  a  single  one?  If  even  1,000  parasites 
are  present  in  a  man  of  10  stone  weight,  the  chances  are  that 
we  must  search  15,000,000,000  haematids  before  we  find  one 
parasite.  At  the  rate  of  10,000  haematids  a  minute  we  shall 
have  to  search  for  1,500,000  minutes,  or  for  twelve  hours  a 
day  for  more  than  five  years,  before  we  succeed.  Or  we  may 
put  it  in  this  way — that  150,000  examinations,  each  of  ten 
minutes'  duration,  must  be  made. 

In  seven  autopsies  on  cases  of  "  latent  malaria,"  C.  F.  Craig 
[1909]  found  only  the  ordinary  parasites  in  the  spleen.  Four 
of  these  contained  malignant  parasites,  yet  no  crescents  at  all 
were  found  in  the  spleen. 

(5).  Probable  cause  of  the  rallies  and  relapses. — According  to 
this  simple  hypothesis  (which  I  will  continue  to  adopt  until  a 
better  one  is  established)  the  rallies  are  probably  due  to  a 
great  destruction  of  the  parasites  by  some  germicidal  power 
of  the  blood,  or  of  their  toxin  by  some  antitoxic  power,  or 
more  generally  to  both.  And  the  relapses  are  probably  due 
to  decrease  in  both  of  these  factors  of  resistance. 


ii6  THE   PARASITIC   INVASION    IN   MAN  [Sect. 

It  is  not  within  our  province  to  discuss  these  factors  now. 
The  general  experience  that  many  cases  improve  without 
treatment,  and  merely  after  good  food  and  rest  in  bed,  proves 
that  such  factors  exist ;  and,  as  already  stated,  if  they  did  not 
exist  every  case  would  certainly  perish. 

Many  diseases  —  tuberculosis,  trypanosomiasis,  relapsing 
fever,  leprosy,  etc. — exhibit  such  variations  in  intensity.  We 
picture  to  ourselves  a  long  struggle  between  the  invaders  and 
the  opposing  force  —  first  one  side  triumphs  and  then  the 
other,  and  death  or  recovery  finally  ends  the  contest. 

Just  as  rest  and  good  food  encourage  the  resistance,  so, 
probably,  anything  which  weakens  the  patient — fatigue,  chill, 
heat,  dissipation,  other  sickness  —  tends  to  encourage  the 
parasites.  Educated  patients  often  declare  that  their  fever  is 
brought  on  by  such  causes.  Military  surgeons  recognise  that 
when  infected  troops  are  despatched  upon  arduous  military 
duties  numbers  of  them  begin  to  fall  sick  at  once,  even  though 
it  may  not  be  the  season  of  fresh  infections.  Travellers  and 
planters  complain  of  the  same  thing  as  regards  their  porters 
or  coolies  ;  and  medical  men  notice  the  frequency  of  malarial 
relapses  after  typhoid  fever,  venereal  diseases,  child  -  birth, 
accidents,  etc.  ■ 

I  think  that  external  heat  probably  tends  to  encourage 
relapses.  Although  the  temperature  of  the  body  remains  much 
the  same,  the  parasites  may  possibly  be  stimulated  by  the 
heat  in  some  way,  owing  to  the  fact  that  warm  climates  are 
specially  suitable  to  them  and  to  their  dissemination  by 
mosquitos.  Thus  in  my  experiments  on  birds  in  1898,  I 
noticed  that  when  the  birds  were  taken  to  the  cool  climate 
of  the  Himalayas  their  parasites  greatly  diminished,  and  when 
they  were  brought  back  again  to  Calcutta  their  parasites 
increased  again.  In  the  hot  weather  in  Calcutta  11^  of  the 
sparrows  examined  contained  P.  danilevskyi\  but  early  in  the 
cool  weather  few  were  found  to  be  infected.  This  point 
requires  exact  experimental  study.     A.  Caccini  [1902]  thinks 


2o]  CAUSES    OF   RALLIES   AND   RELAPSES  117 

that  excessive  heat  does  not  have  much  effect,  but  notes 
the  frequency  of  relapses  in  benign  tertian  in  spring ;  and  it 
seems  to  me  that  the  onset  of  warm  weather  rather  than  the 
heat  itself  is  most  likely  to  be  the  encouraging  factor,  since 
the  germicidal  power  is  probably  heightened  after  the  first 
relapses  in  spring.  It  is  interesting  to  note  that  in  India  there 
is  generally  a  small  but  well-marked  rise  in  the  admission 
rates  of  troops  at  the  commencement  of  the  warm  weather  in 
March  to  April.  For  example,  I  take  at  random  the  Native 
Troops  on  the  North- West  Frontier,  Indus  Valley,  and  North- 
West  Rajputana  ("  Reports  of  the  Sanitary  Commissioner  with 
the  Government  of  India  "),  and  give  the  averages  for  the  three 
years   1900- 1902. 

AVERAGE   ADMISSIONS. 

Strength   Jan.    Feb.  Mar.   Apr.    May  June    July  Aug.  Sept.      Oct.       Nov.     Dec. 
16,428     379     205     191     285     401     326     420     396     565     1,397     1,152      735 

Here  there  is  a  marked  increase  between  March  and  April, 
that  is,  at  the  commencement  of  the  hot  dry  weather,  long 
before  the  advent  of  the  breeding  season  of  Anophelines.  It 
may,  however,  be  due  to  the  awakening  of  infected  hibernating 
mosquitos  (section  21). 

Why,  if  the  germicidal  power  is  strong  enough  to  destroy 
large  numbers  of  the  parasites,  does  it  not  destroy  all  of  them  ? 
I  presume  that,  as  in  other  forms  of  life,  the  hardiest  individuals 
often  succeed  in  withstanding  the  opposing  forces  unless  they 
are  too  strong  ;  that  a  few  of  the  plasmodia  survive  until  the 
germicidal  power  is  fully  developed — when  the  entire  brood  is 
exterminated. 

What  is  it  that  determines  the  length  of  the  rally,  or 
apyrexial  period  ?  Probably  {a)  the  number  of  plasmodia 
left  alive  at  the  end  of  the  previous  attack,  and  {b)  the  strength 
of  the  germicidal  power  of  the  patient.  If  the  parasites  are 
reduced  to  about  the  number  of  protospores  originally 
inoculated,  and  the  germicidal  power  weakens  rapidly,  the 
former  will  now   multiply  again    at   a    rate   somewhat   similar 


ii8  THE   PARASITIC    INVASION    IN   MAN  [Sect. 

to  their  first  rate  of  proliferation — so  that  the  length  of  the 
apyrexial  period  should  be  roughly  equivalent  to  the  original 
incubation  period.  If  the  germicidal  power  is  strong,  or  is 
fortified  by  quinine,  the  plasmodia  left  alive  after  the  previous 
attack  should  multiply  so  slowly  that  the  apyrexial  period  may 
be  indefinitely  prolonged.  Under  such  circumstances  a  few 
parasites  may  perhaps  continue  to  breed  for  months  in  a 
patient,  without  causing  the  smallest  symptoms,  and  yet,  if 
the  germicidal  power  is  reduced  for  a  moment,  may  be  able 
at  any  time  to  multiply  again  sufificiently  to  produce  another 
attack.  The  same  thing  probably  happens  with  irregular  or 
insufficient  quinine  medication.  The  long  intervals  which  fre- 
quently occur  can  be  explained  equally  well  on  this  hypothesis. 

We  do  not  know  why  the  resistance  of  the  host  should 
be  affected  by  his  general  state  of  health  or  by  external 
conditions.  That  such  is  the  case  affords  another  argument 
against  the  idea  that  the  relapses  are  due  merely  to  some 
normal  development  of  the  parasites.  The  study  of  immunity 
in  malaria  should  yield  important  facts  for  the  study  of 
immunity  in  general.     I   merely  touch   upon  the  subject  here. 

Cases  are  often  reported  in  which  the  patient  during  the 
relapses  suffers  from  malaise,  dyspepsia,  and  so  on,  rather 
than  from  fever,  although  the  parasites  are  numerous  enough 
to  be  found.  In  such,  I  presume,  the  antitoxic  power  of  the 
blood  has  become  better  developed  than  the  germicidal  power. 
Cases  in  which  a  relapse  immediately  follows  a  chill  or  accident 
are  explained  perhaps  by  the  hypothesis  that  the  chill  or 
accident  has  immediately  reduced  the  antitoxic  (not  necessarily 
the  germicidal)  power  of  the  blood. 

(6).  Frequency  of  the  relapses. — All  clinicians  recognise  that 
in  untreated  or  badly-treated  cases  a  considerable  number  of 
relapses  may  occur  before  complete  recovery  is  established. 
Cases  giving  a  history  of  say  three  to  ten  relapses  are  very 
common.  But  we  are  indebted  to  A.  Caccini  [1902]  for 
giving  us  a  very  able  and  full  analysis  of  this  question.     In 


2o]  FREQUENCY   OF   RELAPSES  119 

1899- 1901  he  was  entrusted  by  Professor  Ballori,  Director- 
General  of  the  Hospitals  in  Rome,  with  the  care  of  a  special 
department  for  the  study  of  malaria,  and  set  himself  to  the 
task  of  examining  these  questions  methodically.  The  cases 
studied  by  him  were  as  follows : — 

Type                                          First  Attacks  Relapses  Total 

Quartan 525             330  855 

Benign  Tertian         .         .        .         1,086             934  2,020 

Malignant         ....         2,275  i»429  3,704 

Totals         .        .        .        3,886         2,693  6,579 

Many  of  the  cases  were  given  quinine,  so  that  this  proportion 
will  not  accurately  represent  the  proportion  of  relapses  in 
untreated  cases — which  should  be  much  larger.  The  author 
excluded  all  cases  in  which  the  parasites  were  not  found. 
He  endeavoured  to  ascertain  as  exactly  as  possible  the  history 
of  each  case,  not  only  by  enquiry  of  each  patient,  but  by 
reference  to  hospitals  and  localities  where  they  had  been 
treated  ;  he  kept  many  cases  in  hospital  for  long  periods,  and 
he  gives  a  careful  record  of  his  results,  I  will  mention  here 
only  his  untreated  cases. 

Two  cases  of  benign  tertian,  untreated,  were  kept  under 
observation  in  bed  in  hospital  for  nine  months.  The  following 
table  gives  the  duration  in  days  of  their  successive  relapses  and 
rallies : — 

Rel.  Ral.  Rel.  Ral.  Rel.  Ral.  Rel.  Ral.  Rel.  Ral.  Rel. 
Case  I  .  .  .  17  13  16  16  14  19  15  17  12  10  19 
Case  2  .    .    .        15   17   16   15   18   20   17    6   10   9 

Both  patients  were  robust,  had  the  same  diet,  and  were  not 
allowed  to  suffer  from  cold  or  damp  or  intercurrent  affections. 
Nineteen  similar  cases  studied  for  shorter  periods  showed  the 
same  phenomena.  The  author  notes  that  out  of  120  untreated 
cases  of  benign  tertian,  the  relapses  occurred  more  frequently 
in  the  spring  (March  to  May).  He  thinks  that  the  rallies  con- 
tinue from  5  to  18  days,  which  he  calls  apyrexial  periods  of 
short  interval.     But  he  also  notes  and  distinguishes  rallies  of 


I20  THE   PARASITIC   INVASION    IN   MAN  [Sect. 

long  interval,  lasting  3  to  4  months,  which  he  says  occurred  in 
152  persons  who  had  not  revisited  malarious  places  in  the  mean- 
while. The  rally  lasted  under  2  months  in  60  cases  ;  under  70 
days  in  29  cases  ;  90  days  in  20  cases  ;  and  from  90  to  120  days 
in  the  remaining  cases. 

He  also  quotes  the  case  of  a  band  of  75  Calabrian  workmen 
who  had  become  infected  at  Foggio  in  July  1900,  and  had  sub- 
sequently taken  quinine  until  December.  On  8th  September 
1901,  14  months  after  the  first  infection,  62  of  these  men  were 
exposed  to  a  severe  wetting  with  rain,  while  the  remaining  13 
found  shelter.  On  loth  September  and  the  six  following  days, 
every  one  of  these  62  men  was  attacked  with  relapses.  The 
intervening  rallies  since  their  last  attacks  had  lasted  for  7 
months  in  2  of  the  men  ;  for  7-5  months  in  3  ;  for  8  months 
in  12;  for  9  months  in  10;  for  10  months  in  15;  and  for  13 
months  in  20.  Those  who  had  not  been  wetted  by  rain  escaped. 
It  is  supposed  that  none  of  the  cases  had  been  subject  to  re- 
infection. 

In  quartan  the  author  found  that  out  of  118  cases  kept 
without  treatment  relapses  occurred  only  in  8  which  had  been 
exposed  to  chills  and  other  predisposing  causes.  He  thinks 
that  quartan  relapses  chiefly  as  a  consequence  of  such  causes 
— unlike  tertian,  which  relapses  under  any  conditions.  The 
length  of  the  rally  depends  upon  the  care  which  has  been  taken  of 
the  patient ;  but  the  author  quotes  six  cases  of  relapse  occurring 
after  long  intervals  (6  to  10  months).  He  says  also  that  in 
some  cases  of  experimental  inoculation  of  quartan  by  him  (no 
reference)  the  incubation  period  could  be  prolonged  at  pleasure 
by  keeping  the  subject  at  rest  in  bed,  etc. 

Regarding  malignant  fever,  Caccini  gives  the  following 
lengths  of  the  rallies  in  44  untreated  persons  : — 


Days  . 

5 

6 

7 

8 

9 

10 

II 

12 

13 

14 

15 

16 

17 

18 

19 

20 

21 

Cases  . 

9 

I 

5 

I 

7 

I 

I 

I 

I 

I 

I 

I 

2 

6 

1 

3 

2 

The  author  suggests  that  there  is  some  radical  difference 
between   relapses  at  short  and  at  long  intervals,  but  I  cannot 


2o]  FREQUENCY   OF   RELAPSES  121 

find  that  he  proves  his  case.  He  agrees  with  all  observers  in 
attaching  great  importance  to  the  determining  factors  of  relapse, 
which  he  says  are, 

(i)  absence  of  good  food  and  health, 

(2)  gastro-intestinal  troubles, 

(3)  fatigue, 

(4)  traumatism, 

(5)  sudden  chills,  damp,  and  wetting, 

(6)  change  of  climate, 

(7)  certain   foods    and  medicines    (?)  due   to   intestinal 

disturbance, 

(8)  intercurrent  sickness. 
To  these  I  would  add  : — 

(9)  anxiety,  sorrow,  shock  or  fright, 

(10)  alcoholic  and  other  excess, 

(11)  sudden  exposure  to  a  tropical  sun, 

(12)  premature  cessation  of  quinine. 

It  is,  of  course,  understood  that  these  determinants  act  by 
reducing  temporarily  the  host's  resistance,  but  we  do  not  know 
exactly  how  they  do  so. 

Caccini  endorses  the  common  opinion  that  quartan  and  tertian, 
especially  the  former,  are  most  prone  to  relapses.  In  malignant, 
the  original  illness  is  more  severe  and  (probably  for  this  reason) 
relapses  are  not  so  common.  I  will  refer  to  his  important  results 
with  quinine  in  section  23. 

Celli  [1901]  gives  a  useful  table  showing  primary  cases, 
relapses  and  pernicious  cases  in  the  Roman  Hospitals  for 
1 892- 1 898.     The  following  are  the  totals  for  the  seven  years  : — 

Jan.    Feb.    Mar.  Apr.  May  June  July  Aug.  Sept.  Oct.  Nov.  Dec.  Total 

Primary     864    676    724    793  809    696  2,912  5,157  4,440  3,875  3,074  1,967  25,987 

Relapses     581    358    319    341  353    205  522  949  1,031  1,156  989  716  7,520 

Pernicious      21     —      —  —         i  45  62         67  64  56  32  330 

Thus,  excluding  the  pernicious  attacks,  out  of  a  total  of  33,507 
cases,  75%  were  reported  to  be  primary  and  25%  relapses — that 
is,  three  to  one. 


f22  THE    PARASITIC    INVASION    IN    MAN  [Sfxt. 

Relapses  are  referred  to  in  many  other  works,  but  the  informa- 
tion given  is  scanty.  The  illness  being  generally  slighter,  patients 
do  not  often  come  to  hospital  in  consequence  of  it ;  and  in  most 
cases  quinine  distorts  the  clinical  picture  (section  22). 

Relapses  after  long  intervals  are  frequently  mentioned.  The 
case  of  P.  T.  Manson  (section  16,  case  5),  who  had  a  relapse 
nine  months  after  the  original  infection,  followed  by  three 
months'  quinine  treatment,  is  well  known.  In  one  case  at  the 
Royal  Southern  Hospital  I  found  the  parasites  in  a  patient  who 
said  that  he  had  left  the  tropics  four  years  previously  (records 
unfortunately  lost).  In  Britain  we  have  many  returned  officials 
who  say  that  they  continue  to  have  occasional  attacks  after 
return  from  malarious  colonies — more  than  twenty  years  have 
been  mentioned  to  me  by  three  persons ;  but  as  each  attack 
lasts  only  for  a  day  or  two  it  is  generally  impossible  to  verify  the 
point  microscopically.  My  father  left  India  in  1880,  but  in  1889 
still  complained  of  occasional  attacks.  A  little  later  I  witnessed 
one  of  these — a  sudden  severe  rigor  followed  by  high  fever  and  a 
typical  sweating  stage.  The  blood  was  not  examined,  but  the 
paroxysm  was  almost  certainly  a  quartan  or  tertian  one.  So 
far  as  I  remember  there  was  no  determining  factor  in  this  case. 

21.  Average  Duration  of  Untreated  Infections.— Persons 

may  therefore  remain  infected  for  several,  and  possibly  for 
many  years ;  just  as  some  may  recover  spontaneously  after 
the  first  series  of  attacks.  But  from  the  public  health  point 
of  view  an  important  question  remains  to  be  answered,  namely, 
how  long  does  the  infection  continue  in  untreated  cases  on  the 
average}  That  is,  if  1,000  persons,  simultaneously  infected, 
were  to  be  removed  simultaneously  to  a  perfectly  healthy 
area,  where  they  are  kept  untreated,  how  long  would  their 
infections  continue.?  It  is  impossible  to  say  at  which  particular 
moment  the  last  parasite  dies  out  in  a  patient's  blood,  and 
no  adequate  researches  have  been  made  on  the  point.  We 
are  therefore  forced  to  rely  upon  certain  calculations. 


2i]  DURATION   OF    INFECTION  123 

The  cases  of  malaria  at  Ismailia  from   1900-1905  are  given 
officially  as  follows  : — 


Years     . 

1900 

1901 

1902 

1903 

1904 

1905 

Cases     . 

.       2,284 

1,990 

1,551 

214 

90 

37 

In  1901-1902  quinine  was  largely  distributed  in  the  town, 
but  after  my  visit  at  the  end  of  1902  the  Anophelines  were 
banished,  the  quinine  also  being  continued  to  those  who  took 
it.  Since  1905,  and  probably  since  1902,  there  has  been  no 
endemic  malaria,  such  cases  as  occur  being  found  only  in 
persons  infected  outside,  or  being  merely  relapses.  Hence 
we  infer,  as  a  very  rough  calculation,  that  of  the  1,551  persons 
who  were  ill  in  1902,  less  than  1/7  (214)  remained  ill  in  1903, 
and  less  than  1/17  (90)  remained  ill  after  two  years.  But  here 
quinine  expedited  the  recovery  on  one  side  of  the  account ; 
while  on  the  other  side  of  it  many  of  the  cases  that  remained 
were  probably  due  to  external  infection. 

Another  way  to  estimate  the  reduction  is,  I  suggest,  to 
consider  the  statistics  of  some  country  where  fresh  infections 
suddenly  cease  owing  to  the  abrupt  onset  of  a  sharp  winter  and 
the  consequent  cessation  of  mosquito  breeding  and  mosquito 
biting.  I  select  as  an  example  the  Punjab,  a  large  malarious 
area  in  the  extreme  north-west  corner  of  India,  and  give 
the  figures  of  admissions  furnished  by  the  annual  "  Reports 
of  the  Sanitary  Commissioner  with  the  Government  of  India." 

The  years  1899  to  1903  have  been  selected  because  after 
the  latter  date  quinine  began  to  be  administered  much  more 
regularly.  Nevertheless,  subsequent  figures  show  very  similar 
monthly  variations — as  in  fact  are  shown  by  the  same  statistics 
for  other  parts  of  India. 

The  ratios  under  each  monthly  average  are  obtained  by 
dividing  by  it  the  following  monthly  average — so  that  these 
ratios  give  the  monthly  factor  of  increase  or  decrease  in  the 
number  of  admissions. 

The  striking  regularity  with  which  the  maximum  is  reached 
in  October  and  the  minimum   in   February  will  be  observed. 


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126  THE   PARASITIC   INVASION    IN    MAN  [Sect. 

For  the  European  troops  the  maximum  (835)  is  6-47  times 
the  maximum  (129),  which  occurs  four  months  later.  For 
the  native  troops,  the  maximum  (2,955)  is  6-41  times  the 
minimum  (461) — almost  the  same.  For  the  prisoners  the 
maximum  (1,045)  is  3*93  times  the  minimum  (266) — a  smaller 
ratio. 

Thus,  for  1,000  admissions  in  each  class  during  October 
the  following  numbers  were  admitted  in  February: — 

October  February 

European  troops         .        .        .         1,000  154 

Native  troops      ....         1,000  156 

Prisoners 1,000  254 

A  certain  amount  of  quinine  was  doubtless  given  to  all 
these  classes,  and  many  of  the  Europeans  were  probably 
moved  to  hill  stations  after  April  to  May.  It  is  easy  to  under- 
stand the  small  rate  of  recuperation  of  the  prisoners  —  a 
constantly  changing  class  drawn  from  the  lowest  ranks  of 
the  population  and  depressed  by  their  imprisonment.  Hence 
I  infer  that  the  rate  of  recovery  of  the  European  and  native 
troops  during  the  four  months  is  probably  too  favourable 
for  an  estimate  of  the  same  rate  among  a  large  untreated 
native  population.  On  the  other  hand,  the  quinine'  treatment 
of  the  prisoners  may  be  cancelled  by  their  circumstances, 
so  that  their  rate  of  recovery  should  be  something  similar 
to  that  of  the  general  population.  We  may  therefore,  perhaps, 
assume  as  a  rough  but  convenient  estimate  for  the  latter  that 
what  may  be  called  the  reduction  factor  is  about  0*25  in  four 
months — that  is,  that  1,000  cases  should  be  reduced  to  250 
in  that  time  by  spontaneous  improvement. 

We  observe  in  the  statistics  given  above  that  there  is  an 
almost  constant  but  slow  increase  in  the  admissions  from 
February  onward.  Whether  this  is  at  first  due  to  heat  relapses 
or  to  infections  by  hibernating  Anophelines  (section  20)  is 
not  known  ;  but  if  no  such  increase  were  to  take  place,  we 
might  suppose  that  the  same  rate  of  recovery  would  hold  for 


22]  ENLARGEMENT   OF   THE   SPLEEN  127 

the  rest  of  that  year.  In  other  words,  we  might  suppose  that 
any  number  of  patients  brought  to  England  would  be  reduced 
by  recovery  to  one  quarter  (0*25)  every  four  months  —  that 
1,000  cases  would  become  250,  62,  15,  in  four,  eight,  twelve 
months  respectively,  and  so  on.  This  is,  I  fear,  a  very  rough 
estimate,  but  I  know  of  no  other  method  of  making  any 
estimate  at  all. 

Hence  we  may  perhaps  infer  that  3/4  of  our  untreated  cases 
will  recover  in  four  months;  i5/i6of  them  in  eight  months;  31/32 
of  them  in  a  year,  and  so  on.  But  these  figures  are  based  upon 
the  gaol  statistics  of  the  Punjab — that  is,  upon  those  of  natives, 
most  of  whom  have  probably  had  malaria  in  childhood.  What 
may  happen  in  the  case  of  a  completely  non-immune  and 
untreated  population  I  cannot  say.  For  such  we  might  adopt 
a  still  lower  rate  of  recovery,  say  1/2  or  50%  every  three 
months ;  that  is,  1/2  would  recover  in  three  months,  3/4  in  six 
months,  7/8  in  nine  months,  and  15/16  in  a  year.  On  the  whole, 
this  is  probably  the  nearest  estimate. 

Celli  [1901]  gives  the  admissions  into  the  Roman  Hospitals 
during  thirteen  of  the  years  between  1864  and  1898 — numbering 
nearly  93,000  altogether.  I  subjoin  the  monthly  totals  for  the 
reader  to  study  in  connection  with  the  above  remarks. 

Jan.      Feb.     Mar.      Apr.      May      June     July      Aug.      Sept.        Oct.      Nov.      Dec.      Total 
4.673    3.732    3)9o6    3,921     3,575     2,553     8,844     17,678     15,203    12,755    9,531     6,621     92,992 

22.  Enlargement  of  the  Spleen  and  Liver.— This  is  a  con- 
dition of  importance  in  the  prevention  of  malaria,  as  it  often 
enables  us  to  estimate  the  amount  of  the  disease  in  a  locality. 
We  must  now  note  the  following  points  regarding  it. 

The  average  weight  of  the  spleen  of  a  healthy  man  of 
60  kilograms  in  weight  is  estimated  to  be  171  grams  (Vierordt), 
or  2'85/iooo  of  body-weight.  In  healthy  adults  the  edge  of  it 
cannot  be  felt  under  the  ribs,  but  the  reader  should  note  that  this 
can  often  be  done  in  small  infants. 

The   organ    commences   to   enlarge   during   even    the   first 


128  THE   PARASITIC    INVASION    IN    MAN  [Sect. 

paroxysm  of  malarial  fever,  the  increase  in  the  area  of  splenic, 
dullness  being  quite  appreciable.  In  the  first  apyrexial  period 
the  enlargement  decreases,  but  as  attack  follows  attack  the 
sum  of  the  successive  increments  is  greater  than  that  of  the 
successive  decrements,  so  that  a  more  and  more  marked  tumour 
results.  Innumerable  measurements  have  been  recorded. 
Kelsch  and  Kiener  [1889]  state  that  in  eighty  autopsies  they 
found  the  weight  to  vary  from  400  to  1,500  grams,  and  to 
average  914  grams  (chronic  malaria). 

I  think  that  even  small  and  irregularly  administered  doses 
of  quinine  tend  to  check  the  increase  very  much.  Thus  in 
untreated  native  children  one  often  finds  the  organ  an  inch 
or  more  below  the  ribs  after  a  few  attacks,  while  there  is 
frequently  no  enlargement  in  Europeans  even  after  many 
attacks.  In  sailors  who  have  reached  Liverpool  after  weeks' 
or  months'  fever  on  the  homeward  voyage  from  West  Africa, 
we  find  as  a  rule  scarcely  any  enlargement.  In  1895  my 
regiment  in  Secunderabad,  India,  was  full  of  malaria  as  proved 
by  the  microscope  and  the  clinical  symptoms,  but  on  making 
a  spleen  census  by  order  of  the  authorities  I  found  only  four 
men  with  enlarged  spleen  out  of  about  eight  hundred.  In 
both  these  instances  a  certain  amount  of  quinine'  is  or  was 
given — not  enough  to  cure  the  patient,  but  enough  to  check 
the  splenomegaly. 

The  pathological  changes  are  discussed  in  detail  in  the 
text-books  and  need  not  be  described  here.  Laveran  [1907, 
p.  391]  considers  the  pathology  and  seems  to  think  that  the 
enlargement  is  due  to  local  irritation  caused  by  the  accumula- 
tion of  the  parasites  in  the  organs,  which  is  their  "  siege 
d'election."  Others  connect  the  enlargement  with  the  defensive 
process.  The  arguments  are  far  from  conclusive  on  either 
side. 

On  the  whole,  from  general  observation,  I  consider  that 
the  following  propositions  are  probably  true : — 

(i).  That   in    a   given    number   of  infections  of  the  same 


22]  ENLARGEMENT   OF   THE   SPLEEN  129 

duration    (a)    in    children    and    (d)   in    adults,   the 
children  will  show  a  greater  degree  of  splenomegaly. 
(2).  That  in  a  given  number  of  infections  of  the  same  dura- 
tion (a)  in  Indo-Europeans  and  (3)  in  Negroes,  the 
former  will  show  a  greater  degree  of  splenomegaly. 
I  cannot  speak  regarding  Mongolians. 
(3).  That  in  a  given   number   of  infections    of  the  same 
duration  (a)  in  untreated  persons  and  (d)  in  persons 
of  the  same  age  and  race  treated  even  slightly  with 
quinine,  the  former  will  show  a  greater  degree  of 
splenomegaly. 
(4).  That  in  a   given    number  of  infections   of  the  same 
duration  (a)  in  persons  infected  only  once,  and  (d) 
in    persons    who    have   been   subject    to    repeated 
infections,  the  latter  will    show  the  greater  degree 
of  splenomegaly. 
(5).  That  the  number  of  parasites  tends  to  vary  inversely 
as  the  degree  of  splenomegaly ;    that   is,   that   the 
parasites  tend  to  die  out  in  persons  with  very  large 
spleen. 
(6),  That  a   hot  and    damp   climate,  or   insufficient   food, 
or  certain  diets,  or  bad  drinking  water  may  possibly 
favour  the  development  of  splenomegaly ;  in  other 
words,   that  the  degree   of  splenomegaly  may   not 
always    be    an    exact   measure   of    the   amount   of 
malaria  in  a  locality. 
I  cannot  give  anything  approaching  proof  of  these  proposi- 
tions, but  merely  suggest   them    for   future  consideration   and 
investigation. 

On  the  other  hand,  some  general  facts  have  been  more 
strictly  ascertained.  Before  considering  them  we  should 
remember  that  many  of  the  older  observations  have  been 
invalidated  by  the  discovery  in  1903  that  kala-azar  a  disease 
which  causes  great  enlargement  of  the  spleen  and  liver  and 
abounds  in  parts  of  India,  Algeria  and  other  countries,  is  not 

I 


I30  THE   PARASITIC    INVASION    IN   MAN  [Sect. 

malaria,  but  is  due  to  a  different  organism,  Leishmania  donovani, 
Laveran.  Before  this  date  the  two  diseases  were  frequently 
confounded,  as,  for  instance,  by  myself  in  my  report  on 
kala-azar  [1899].  If  therefore  we  wish  for  accurate  figures 
we  must  first  ascertain  whether  kala-azar  is  present  or  not,  or 
at  least  whether  it  is  very  prevalent.  This  is  generally  not 
difficult,  for  the  following  reasons  : — 

(i).  Kala-azar    is    extremely    fatal,    whereas     malaria     is 
benign  ;  so  that  the  presence  of  the  former  is  soon 
felt  in  a  locality, 
(2).  The  parasites  of  both  diseases  can  be  detected  during 

life  and  post-mortem. 
(3).  The  symptoms  of  kala-azar,  though  somewhat  similar 
to  those  of  malaria,  are  much  more  intense.     The 
patients  often  have  a  look  of  suffering  and   melan- 
choly not  so  frequently  observed  in  malaria.     I  was 
much   struck    with  this  difference  when  comparing 
splenomegalous   children    in    Greece  and  Mauritius 
with  those  suffering  from  kala-azar  in  Assam. 
In    the   absence  of  this   disease,   then,   we   may   generally 
ascribe  most   of  the   cases   of  enlargement   of  the   spleen   to 
malaria,  especially  if  they  are  numerous.     They  are  generally 
extremely  numerous  in  most  malarious  localities  where  quinine 
is  not  much  taken. 

In  1907- 1 908  Major  Fowler  and  I,  assisted  by  the  Sanitary 
Department  and  the  medical  men  of  Mauritius,  made  a  large 
"  spleen  census "  in  that  colony.  We  examined  children  of 
fifteen  years  of  age  and  under,  in  all  parts  of  the  island.  Out 
of  an  estimated  total  of  182,000  such  children  we  tested  31,022, 
and  found  enlargement  of  the  spleen  in  10,595,  or  more  than 
one-third  (34'i/ioo).  Moreover,  in  30,137  we  recorded  the  degree 
of  enlargement,  and  found  that  it  was  small  in  4,381,  or  14-5/100  ; 
medium  in  3,479  or  11-5/100;  and  great  in  2,566  or  8-5/100— a 
total  of  10,426  with  enlargement. 

This  differentiation  of  degree   suggests   the   possibility    of 


22]  ENLARGEMENT   OF   THE   SPLEEN  131 

obtaining  a  figure  which  I  call  the  average  spleen  index. 
Taking  a  normal  spleen  at  171  grams,  a  very  large  spleen  of 
1,500  grams  would  be  about  nine  times  that  size.  We  may 
therefore  define  a  small  enlargement  as  being  about  three 
times  the  normal  size  ;  a  mediuui  enlargement  about  six  times 
the  normal  ;  and  a  great  enlargement  about  nine  times  the 
normal — the  same  ratios  holding  for  children  also.  Thus  in 
order  to  find  the  average  spleen,  we  multiply  the  numbers 
under  each  heading  by  the  size-ratio,  add  the  results  to  the 
number  of  children  with  no  enlargement,  and  divide  by  the 
total  number  of  children  examined.  We  thus  have  (19,71  i-j- 
4,381  X  3 +  3,479x6  + 2,566x9) -^30,1 37  =  2*54  the  average  spleen 
for  Mauritius  (section  31). 

From  these  and  other  data  I  compiled  the  following  tables 
[1908]  showing  the  relation  between  the  spleen  rates  and 
altitude,  and  the  spleen  rates  and  the  general  death  rates  in 
Mauritius. 


SPLEEN    RATES   ACCORDING   TO   ALTITUDE  ( 

'Mauritius). 

Altitude 
in  Feet. 

Children 
examined. 

Spl 

sens. 

Total  with 
spleen. 

Spleen 
rate. 

Average 
spleen. 

I 

3 

6 

9 

100 

5,210 

2,623 

1,030 

732 

734 

2,587 

49-6 

3-20 

200 

4,843 

2,593 

813 

765 

633 

1,250 

46-4 

3-i6 

300 

3,559 

2,208 

616 

457 

258 

1,351 

37-6 

2-59 

400 

2,817 

1,432 

651 

473 

262 

1,386 

49-2 

3-01 

500 

1,246 

786 

193 

177 

90 

460 

36-9 

3-48 

600 

830 

518 

106 

128 

78 

312 

37-5 

274 

700 

1,963 

1,373 

227 

235 

122 

590 

30-0 

2-27 

800 

1,398 

1,241 

80 

41 

36 

157 

in 

1-65 

900 

624 

478 

52 

48 

46 

146 

23-4 

2-14 

1,000 

972 

901 

47 

II 

13 

71 

73 

1-26 

1,100 

782 

736 

18 

9 

7 

46 

5-8 

I-I4 

1,200 

858 

751 

49 

28 

'9 

107 

12-4 

1-28 

1,300 

130 

124 

6 

4-6 

1,400 

1,991 

1,556 

185 

160 

90 

435 

21-8 

194 

1,500 

612 

586 

10 

12 

4 

26 

4-2 

119 

1,600 

112 

105 

3 

4 

7 

6-2 

1-31 

1,700 

... 

... 

1,800 

765 

740 

13 

"6 

5 

25 

3-2 

113 

132 


THE   PARASITIC    INVASION    IN    MAN 


[Sect. 


SPLEEN   RATES   COMPARED   WITH    DEATH    RATES 
BY  DISTRICTS— (Mauritius) 


Class. 

Districts. 

Death  rates 
Average 
1905-1906. 

Spleen 
rates. 

Average 
spleen. 

Pamplemousses 

zrz 

39'6 

2-62 

Riviere  du  Rampart 

307 

24-6 

1-97 

Flacq 

30  "9 

59-6 

3-45 

Estates  only 

Grand  Port 

24-5 

48-0 

3-25 

Savanne 

287 

21-5 

1-85 

Black  River 

39-5 

567 

3-56 

Moka 

187 

4 '4 

1-23 

■  Plaines  Wilhems 

27'0 

8-6 

1-43 

Average  of  the  above 

297 

32-9 

2-42 

/Port  Louis 

36-6 

35-6 

2-66 

Pamplemousses 

46-1 

457 

3 '04 

Riviere  du  Rampart 

397 

27-6 

2*12 

Flacq 

42-4 

627 

3-89 

All  Classes 

-  Grand  Port 

38-6 

42-4 

2-97 

Savanne 

32-5 

23-0 

1-96 

Black  River 

44-2 

58-2 

3-63 

Moka 

31-1 

II-2 

1-52 

^Plaines  Wilhems 

31-9 

14-3 

I -61 

Average  of  the  above 

40-3 

35-6 

2  "60 

The  exceptionally  high  figures  at  an  altitude  of  1,400  feet 
(426  meters)  were  due  to  a  serious  local  outbreak  at  the  large 
village  of  Phoenix  in  Plaines  Wilhelms  district,  most  of  which 
is  high  and  healthy.  It  should  be  understood  that  the  higher 
altitudes  in  Mauritius  are  plateaus  rather  than  sloped  hillsides, 
so  that  the  variation  is  probably  due  merely  to  difference  of 
climate.  The  accepted  rule  is  that  the  temperature  falls  i"  F. 
for  every  300  feet  (or  1°  C.  for  i6^'6  metres)  of  altitude. 

A  still  larger  spleen  census  was  carried  out  in  Ceylon 
towards  the  end  of  1908  by  the  orders  of  the  Principal  Civil 
Medical  Officer  (Sir  Allan  Perry).  He  estimated  that  the  total 
number  of  children  under  fifteen  years  in  that  island  were 
1,622,766,  and  the  following  table  gives  the  result  of  the  census 
("  Report  of  the  Advisory  Committee  for  the  Tropical  Diseases 


22] 


ENLARGEMENT   OF   THE   SPLEEN 


133 


Research    Fund    for   the   year   1909" — Blue  Book  of  Colonial 
Office). 


Province. 

Children 
examined . 

Enlargement  of  spleen. 

Spleen 
Rate. 

Average 
Spleen. 

Total. 

Small. 

Medium. 

Great. 

Northern  . 

Southern  . 

Eastern     . 

N.  Western 
1  N.  Central 
i  Uva  . 

Sabaragamuwa 

Central     . 

Western   . 
1 

11,371 

15,022 

6,476 

17,024 

5,087 

5,177 

7,154 

14,362 

10,585 

5,438 
2,847 
2,266 
9,064 

3,215 
2,291 
2,046 
2,804 
2,350 

31,421 

2,567 
1,794 
1,449 
4,675 
1,491 
1,088 
1,049 
1,631 
1,867 

1,194 
600 

572 

2,975 

1,100 

686 

527 
817 

417 
8,888 

777 
453 
245 
1,414 
624 

517 
470 

356 
66 

4,922 

39-91 
18-95 

34-99 
53-25 
63-20 
44-20 
28-60 
19-52 
22-20 

34-05 

2-52 
1-67 
2-19 
3-08 

3-64 
2-88 
2-i8 
1-70 
1-59 

Total 

92,258 

17,611 

2*29 

These  large  figures  correspond  closely  with  those  obtained  in 
Mauritius.  They  give  not  only  valuable  information  regarding 
the  local  prevalence  of  malaria,  but  show  how  enormously  wide- 
spread the  disease  must  be — for  neither  Ceylon  nor  Mauritius 
can  be  called  very  extremely  malarious.  The  figures  in  Ceylon 
were  collected  after  the  malaria  season,  and  those  of  Mauritius 
during  the  early  part  of  the  season. 

The  correspondence  between  the  spleen  rate  and  the  number 
of  persons  found  to  contain  the  parasites  will  be  discussed  in 
section  31  (2). 

According  to  theory  the  spleen  rate  should  fall  with  the 
distance  from  marshes.  This  point  was  carefully  worked  out 
by  Major  Fowler  and  myself  in  the  outbreak  at  Phoenix, 
Mauritius.  We  found,  not  only  that  such  a  fall  occurred,  but 
that  it  was  so  extremely  rapid  and  marked  as  to  be  beyond  all 
possibility  of  chance  distribution  (section  30  (i)  and  map). 

The  older  writers  lay  down  that  the  liver  is  generally 
enlarged  in  malaria.  Kelsch  and  Kiener  [1S89]  say  that  its 
average  weight  is  2-3  kilograms,  but  that  it  may  weigh  up  to 


134  THE   PARASITIC   INVASION    IN   MAN  [Sect. 

4  kilograms;  but  they  worked  in  Algeria,  and  it  is  quite  possible 
that  there,  as  elsewhere,  cases  of  kala-azar  were  included.  I 
was  struck  both  in  Greece  and  in  Mauritius,  where  kala-azar 
is  not  supposed  to  exist,  with  the  absence  of  any  marked 
enlargement  of  the  liver  in  the  great  majority  of  the  children 
who  had  splenomegaly.  More  definite  data  are  required  on 
this  subject. 

23.  The  Effect  of  Quinine. — After  the  earlier  physicians 
had  established  the  utility  of  cinchona  for  malaria  it  began  to 
be  much  discredited  owing  to  its  employment  in  doses  too 
small  to  be  effective.  This  error  was  rectified  by  Maillot  [1834], 
who  after  a  long  struggle  persuaded  the  medical  profession  to 
adopt  larger  doses  in  consequence  of  his  experience  in  Algeria. 
But  up  to  the  end  of  last  century,  another  error,  equally  great, 
was  very  generally  made — the  drug  was  not  continued  long 
enough  to  prevent  relapses.  When  I  went  to  India  in  1881 
it  was  the  rule  in  military  practice  to  return  soldiers  to  duty 
three  days  after  the  cessation  of  fever.  I  believe  that  I  was 
one  of  the  first  to  call  attention  to  this  absurdity  [1S96,  p.  43]. 
When  I  myself  was  infected  next  year  I  prescribed  for  myself 
a  rigorous  quinine  treatment  for  four  months,  and  had  no 
relapses  in  consequence  ;  and  I  have  always  taught  this  rule 
since  then.  The  practice  is  now  much  better,  but  I  still  see 
numerous  patients,  especially  from  West  Africa,  who  have  been 
enjoined  to  take  quinine  for  a  fortnight  after  recovery !  Need- 
less to  say,  haemoglobinuria  is  often  the  result.  A  third 
error,  still  often  made,  is  to  withhold  the  drug  until  the  fever 
has  fallen. 

Much  work  has  been  done  on  the  absorption  and  elimination 
of  quinine  by  the  body — more  recently  by  Kleine  [1901], 
Jacoangeli  [1903],  Mariani  [1903 -1904],  Modigliana  [1905], 
Giemsa  and  Schaumann  [1907],  and  others.  The  absorption 
is  measured  by  the  elimination,  which  takes  place  principally 
through  the  urine,  in  which  the  presence  of  the  drug  is  easily 


23]  QUININE  135 

revealed  by  chemical  analysis  ;  and  the  results  may  be  sum- 
marised sufficiently  for  public  health  work  as  follows  : — 

After  intr-avenous  injectiort,  cinchonism  follows  in  a  few 
minutes.  Baccelli,  who  first  suggested  such  injections,  employed 
solutions  of  I  gram  of  quinine  in  10  parts  of  physiological  salt 
solution — to  be  used  only  in  severe  cases. 

After  being  taken  by  the  mouth,  the  first  traces  of  the  drug 
may  begin  to  appear  in  the  urine  in  about  fifteen  minutes  ;  but 
this  period  varies  largely  for  different  salts.  The  maximum 
elimination  occurs  between  four  to  twelve  hours  after  ingestion. 
Most  of  the  drug  is  eliminated  before  thirty-six  hours,  but  traces 
of  it  may  be  found  even  after  nine  days.  Only  about  1/3  of  the 
dose  escapes  destruction  by  the  body.  The  more  soluble  salts 
appear  much  more  quickly  in  the  urine  than  the  less  soluble 
ones,  but  the  latter  are  finally  absorbed  as  well  as  the  former. 
So  also,  the  salts  are  more  quickly  absorbed  from  an  empty 
stomach  ;  but  the  total  amount  absorbed  from  a  full  stomach  is 
finally  quite  as  large.  Given  in  repeated  small  doses,  the  drug 
appears  to  be  better  absorbed  than  when  it  is  given  in  a  single 
dose  of  the  same  total  weight. 

After  intramuscular  injection,  the  salts  are  not  absorbed  so 
quickly,  especially  if  given  in  strong  solution.  This  is  due  to 
local  precipitation  (Giemsa  and  Schaumann).  Thus  while  nearly 
40/100  of  quinine  taken  by  the  stomach  may  be  eliminated 
in  three  days,  only  about  12/100  given  intramuscularly  in  a  i/i 
solution  is  eliminated  in  the  same  time.  But  with  a  i/io  solution 
about  23/100  of  the  salt  (bihydrochloride)  is  eliminated  after 
intramuscular  injection. 

On  the  other  hand,  D.  Sandro  [1909]  favours  intramuscular 
injection  because  absorption  through  the  liver  is  thus  avoided. 
He  also  finds  that  the  drug  remains  longest  in  the  spleen 
(twenty  hours). 

After  rectal  injection,  quinine  appears  in  the  urine  in  twenty- 
five  minutes. 

As  the  drug  is  not  completely  eliminated  for  several  days  it 


136  THE   PARASITIC    INVASION    IN   MAN  [Sect. 

is  cumulative  in  its  action  ;  so  that  a  daily  dose  will  keep  the 
blood  impregnated  with  about  twice  as  much  as  is  given  at  each 
dose  [from  Mariani,  1904].  Fever  does  not  affect  the  absorption, 
but  gastro-intestinal  troubles  do  so  if  severe  enough. 

The  following  table  shows  when  some  of  the  various  salts 
appear  in  the  urine  : — 


Salt. 

Equivalent 

Solubility.  1 

Appears  in 

of  quinine. 1 

urine. 

Bihydrochlorate 

72-0% 

I/I 

15  minutes 

Hydrochlorate 

8r8% 

1/40 

15 

Acetate 

84-0% 

30 

Citrate 

67-0% 

1/820 

30 

Bisulphate 

59-1% 

I/II 

30 

Sulphate 

73-5% 

1/800 

45-      „ 

Tannate 

20*0% 

slight 

180        „ 

Euquinine 

8i-o% 

1/12,500 

For  further  details  the  laborious  papers  referred  to  above, 
especially  those  of  Mariani  and  Giemsa  and  Schaumann,  should 
be  consulted. 

In  large  enough  doses  quinine  produces  ringing  in  the  ears, 
deafness,  giddiness,  headache,  dilatation  of  the  pupils,  urticaria 
and  erythema,  and,  in  poisonous  doses,  convulsions,  muscular 
weakness  and  amblyopia.-  A  very  small  percentage  of  people 
are  unable  to  take  even  small  doses  ;  Dr  Macalister  had  a  case 
in  the  tropical  clinic  of  the  Royal  Southern  Hospital  at 
Liverpool  who  could  not  endure  even  0'03  grams.^  I  have 
observed  in  experiments  on  myself  that  quinine  taken  just 
before  a  meal  causes  tinnitus  auriiim  in  about  half  an  hour, 
thus  proving  its  rapid  absorption  ;  but  taken  after  a  meal  it 
does  not  produce  this  effect  so  quickly,  while  it  tends  to  cause 
much  dyspepsia,  especially  if  given  in  pill  form,  and  leaves  a 

1  Very  variable  figures  are  given.  I  adopt  some  of  those  furnished  to  me  by 
Howards  &  Sons. 

2  G.  Baermann  has  recently  reported  [1909]  a  death  due  to  two  doses  of  1/2  gram 
of  quinine  hydrochlorate — collapse,  blood  in  dejecta,  extravasation  in  organs. 

^  I  have  just  seen  a  patient  who  confessed  to  the  rather  exceptional  drug-habit  of 
quinine.  He  acquired  a  craving  for  it,  and  found  great  difficulty  in  breaking  himself 
of  the  habit. 


23]  QUININE  137 

taste  in  the  mouth  which  remains  until  the  next  meal.  For 
myself,  therefore,  I  always  prefer  to  take  it  just  before  meals, 
especially  before  breakfast.  This  is  also  often  the  best  time, 
according  to  Torti's  law,  for  destroying  the  plasmodia. 

The  action  of  quinine  upon  the  parasites  has  been  studied  by 
many  observers.  Binz  [1867]  was  the  first  to  study  the  effect  of 
weak  solutions  of  quinine  on  Protozoa.  Laveran  states  that  a 
1/10,000  solution  kills  the  plasmodia  in  vitro.  Romanowsky  and 
Mannaberg  [1894]  found  that  in  patients  who  had  been  taking 
quinine  the  parasites  possessed  badly  staining  nuclei,  that  many 
of  the  spores  within  the  sporocysts  were  dead,  and  that  the 
understained  parasites  had  a  peculiar  appearance.  Numerous 
studies  have  been  made  subsequently  on  the  subject,  as  by 
Ziemann  [1906]  and  Craig  [1906],  which  give  a  somewhat 
different  picture  of  the  death-process.  Nearly  all  observers 
have  agreed  that  quinine  exerts  much  less  influence  on  the 
gametids,  especially  the  crescents,  than  upon  the  sporids,  though 
Ziemann  thinks  that  the  male  gametids  are  more  easily 
affected.  Many  of  the  younger  writers  ascribe  relapses  to 
parthenogenesis  in  gametids  which  survive  all  quinine  treat- 
ment in  this  manner.  Gualdi  and  Martirano  [1901]  state  that 
as  much  as  2-5  grams  of  quinine  in  single  dose,  or  i"0-i'5  grams 
daily,  are  not  sufficient  to  banish  crescents.  I  note  that  it 
is  not  always  easy  to  state  that  the  observed  forms  are  really 
due  to  quinine  and  not  to  the  germicidal  action  of  the  blood  ; 
and  indeed  that  they  are  really  abnormal  forms  at  all ;  and 
also  that  strict  enumerative  methods  have  not  been  used. 

An  important  point  in  connection  with  the  prevention  of 
malaria  is  that  Bignami  and  Bastianelli,  Gualdo  and  Martirano, 
and  Schaudinn  [1903]  have  succeeded  in  infecting  Anophelines 
from  patients  who  had  been  taking  quinine.  Schaudinn's  case 
had  been  taking  i  gram  thrice  a  week.  Ziemann  remarks  that 
this  suggests  that  the  male  gametids  are  not  destroyed  as  he 
thought.  It  also  suggests  that  cases  of  crescents  are  likely 
to  prove  sources  of  infection  in  spite  of  energetic  treatment. 


138  THE   PARASITIC   INVASION    IN   MAN  [Sect. 

The  article  of  Caccini  [1902],  which  I  quoted  in  part  in 
section  20,  gives  valuable  information  on  the  effect  of  quinine 
treatment  on  the  prevention  of  relapses,  and  therefore  on  the 
extermination  of  the  invasion.  After  all,  this  is  the  most 
important  part  of  the  subject  from  the  point  of  view  of  pre- 
ventive medicine.  He  summarises  his  cases  of  benign  tertian 
as  follows : — 

(i).  Of  145  cases  treated  early  and  systematically  a  relapse 

occurred  in  37%. 
(2).  Of  301  cases  treated  systematically,  but  started  some- 
what late,  a  relapse  occurred  in  30%. 
(3).  Of  1,002  cases  with  daily  quinine,  a  relapse  occurred 

in  '5%. 
(4).  Of  50  cases  treated  with  quinine  at  height  of  fever, 

a  relapse  occurred  in  80%. 
(5).  Of  55  cases  treated  with  quinine  during  the  sweating 

stage,  a  relapse  occurred  in  80%. 
(6).  Of  291   cases  to  which  quinine  was  given  irregularly, 

a  relapse  occurred  in  85%. 
(7).  Of  120  cases  to  which  quinine  was  not  given   at   all, 
there  was  only  one  in  which  no  relapse  occurred. 
The  author  explains  that  by  "  early  and  systematic  treat- 
ment "  he  means  quinine  given  on  alternate  days  in  doses  of 
i'5-2'0  grams  per  day  in  three  or  four  doses,  with  about  half 
an  hour's  interval  between  them,  starting   the  administration 
three    hours    before    the    (expected)    commencement    of    the 
fever.     But  the  treatment  was  suspended  after  seven  days.     By 
"  systematic  but  late  treatment "  he  means  the  same  scale   of 
treatment  commenced  later  in   the  case.     By  "  daily  quinine " 
he  means  daily  administration  of  1-2  grams  without  reference 
to  the  hour  of  onset  of  fever,  the  treatment  being  suspended 
after  seven  to  te?i  days.     Apparently  in  all  cases  "  the  cure  was 
recommenced  every  time  that  a  relapse  set  in." 
The  figures  prove  fairly  clearly  the  following : — 
(i).  The  best  results   (only  15%   relapses)  were   obtained 
with  daily  doses  of  quinine. 


23]  QUININE    IN    RELAPSES  139 

(2).  Good    results    (only   30-37^   relapses)  were   obtained 

with  the  so-called  systematic  treatment. 
(3).  Bad  results  (80-85//  relapses)  were   obtained    by   the 

use  of  quinine  late  in  the  paroxysm. 
(4).  The  unfortunate  (?    unavoidable)    suspension    of    the 
treatment  after  seven  to  ten   days  has  invalidated 
most  of  the  author's  results  regarding  the  length  of 
the  apyrexial  period,  since,  obviously,  the  parasites 
would   begin  to   multiply  again  from  the  moment 
that  the  quinine  was  stopped  and  would  produce 
another  attack  when,  a  week  or  so  later,  they  had 
multiplied    sufficiently  to    do    so.      It   is   true   that 
he  says  in   his  summary  that  "  though   the   treat- 
ment   is    prolonged    beyond    the    seven    days    the 
relapse   occurs   all   the   same ;     but   this  was  done 
apparently  only  in  twenty  cases  altogether  (so  far  as 
I    can    follow   the    intricacies    of   the    paper),   and, 
as  every  one  in  practice  knows,  to  order  a  medicine 
is  one  thing,  to  get  it  taken  is  another. 
With    regard    to   quartan    fever   there    is    nothing    to    add. 
With  regard  to  malignant  fever  the  author  is  very  emphatic 
on  the  point  that  relapses  occur  between  the  fifth  and  twenty- 
first  days  of  apyrexia,  in  spite  of  energetic  quinine  treatment ; 
for  example,  in   the  case  of  90  work-people  discharged   from 
hospital    after    temporary    cure,    and    792    patients    kept    in 
hospital  for  thirty  days,  all  the  former  and  all  except  24  of  the 
latter  relapsed.     All  that  the  author  is  able  to  admit  is  that 
the  relapses  occurred  sooner  in  those  discharged  from  hospital 
than  in  those  retained  there.     Unfortunately,  he  is  quite  vague 
as  to  the  continuity  of  the  treatment.     In  one  place  he  says 
that  "  this    of  course,  occurred  in  patients  who  had  continued 
the   quinine  treatment  in   doses  of   1-2   grams  per  day,"  and 
in    another   place   that   this   had    been    done   "even    after   the 
cessation  of  the  febrile  attacks,"  but  I   do  not  clearly  gather 
that  the  treatment  had  been  sufficie^it  and  continuous  through- 


I40  THE   PARASITIC   INVASION    IN   MAN  [Sect. 

out.  Obviously  the  whole  investigation,  meritorious  as  it  was, 
has  lost  much  of  its  value  owing  to  the  uncertainty  intro- 
duced by  the  discontinuous  methods  of  quinine  administra- 
tion employed.  Regarding  relapses  after  "  long  intervals " 
the  same  element  of  doubt  exists.  I  suppose  that  as  long 
as  a  single  sporid  remains  alive  in  the  blood,  the  parasites 
may  again  reach  the  pyrogenous  limit  after  a  sufficient 
interval,  if  the  drug  is  discontinued  or  continued  in  insufficient 
doses.  A  very  careful  enquiry  is  demanded  before  we  can 
admit  with  the  author  that  quinine  has  no  effect  on  the 
occurrence  of  such  relapses. 

Subsequently  A.  Carducci  [1905]  made  a  similar  analysis 
of  50-60  cases  at  Rome.  He  infers  that  relapses  at  short 
intervals  occur  from  the  6th-9th  days  of  apyrexia,  mostly 
on  the  7th  day,  but  that  in  quartan  and  tertian  a  relapse 
is  often  passed  over.  He  recommends  i  gram  of  quinine 
on  the  ist,  2nd,  5th,  6th,  8th,  13th,  15th  days  of  apyrexia, 
and  1$  gram  on  the  7th  and  14th  days  in  order  to  check 
this  weekly  return,  and  so  on  for  months  and  months.  With 
this  medication  he  was  able  to  prevent  relapses  in  most  of 
his  cases,  but  remarks  that  they  recurred  if  the  quinine  was 
discontinued. 

On  the  whole,  after  studying  this  and  much  other  literature, 
I  think  that  there  is  probably  no  special  periodicity  in  relapses 
— that  the  periodicity  noted  by  some  observers  was  probably 
due  rather  to  their  own  periodical  methods  of  medication  than 
to  any  other  cause.  If  marked  periodicity  in  relapses  exists,  it 
should  have  been  widely  observed  long  before  now  amongst 
the  immense  number  of  cases  occurring  in  military  practice — 
it  would  certainly  have  been  observed  by  the  military  as  well 
as  by  the  medical  officers.  But  I  can  find  few  notes  to  this 
effect,  and  certainly  remember  nothing  of  the  kind  in  my  own 
practice.  As  stated  in  section  20  (6)  I  am  at  present  inclined 
to  think  that  relapses  occur  after  quite  irregular  intervals, 
determined  by  secondary  causes  or  insufficient  treatment,  rather 


23]  QUININE   IN    RELAPSES  141 

than  by  any  inherent  property  of  the  parasites  ;  but  that  there 
may  be  some  tendency  to  periodical  failure  of  the  germicidal 
powers  (section  65). 

Regarding  the  reputed  failure  of  quinine  to  prevent  relapses, 
I  again  remain  dissatisfied  with  the  evidence.  It  appears  to 
me  to  be  merely  a  question  of  sufficiency  and  continuity  of 
treatment. 

On  the  other  hand,  there  appears  to  be  a  large  mass  of 
evidence  in  favour  of  Torti's  law  that  quinine  should  be 
administered  two  or  three  hours  before  the  commencement 
of  the  paroxysm,  if  this  can  be  determined. 

Many  authors — Laveran,  Koch,  Manson,  Ziemann,  Carducci 
and  others  —  have  suggested  various  systems  of  discontinuous 
dosage,  such  as  the  administration  of  large  doses  once  a  week, 
or  twice  a  week,  or  every  four  days,  or  for  two  consecutive  days 
every  week,  or  every  seven  days  after  the  first  day  of  apyrexia, 
and  so  on.  Owing  to  the  temporary  retention  of  the  drug  in 
the  blood  there  is  difficulty  in  understanding  the  rationale  of 
such  proposals.  Moreover,  a  large  dose  every  few  days  is 
much  more  distressing  to  the  patient  than  a  smaller  dose 
every  day,  and,  for  this  very  reason,  is  apt  to  be  neglected  or 
postponed  by  him.  There  appear  to  be  no  evidence  that  the 
Plasmodia  become  habituated  to  quinine  as  trypanosomes  do  to 
atoxyl.  Personally,  therefore,  I  prefer  the  continuous  method  ; 
that  is,  a  dose  at  least  once  a  day.  It  seems  to  have  given  the 
best  results  in  Caccini's  cases,  and  is  recommended  by  Celli. 
We  should  here  distinguish  carefully  between  what  may  be 
called  medical  and  hygienic  therapeutics.  The  former  is  the 
therapeutics  of  the  physician  at  the  bedside  ;  the  latter,  that 
which  is  to  be  recommended  to  the  general  public — who  are, 
in  fact,  called  upon  to  treat  themselves.  Refinements  in 
medication  which  are  possible  in  the  former  case  are  not 
possible  in  the  latter  one,  and  therefore  the  simplest  possible 
rule  is  the  one  which  is  to  be  preferred  for  hygienic  therapeutics 
(section  36). 


142  THE    PARASITIC    INVASION    IN    MAN  [Sect. 

Regarding  the  duration  of  treatment  required  to  exterminate 
the  parasites,  we  have  no  complete  data.  The  case  of  T.  Manson, 
who  was  infected  in  London  in  1900  and  was  treated  for  three 
months,  relapsed  after  nine  months.  In  India  the  after-treat- 
ment of  the  European  troops  is  continued  for  six  weeks  after 
discharge  from  hospital,  resulting  in  a  considerable  reduction 
in  the  number  of  admissions.  Thus  out  of  ninety  primary 
cases  in  two  stations  there  were  only  seven  relapses  ("  Annual 
Report  of  Sanitary  Commissioner,  1907,"  p.  11).  Teaching  on 
this  point  differs  largely,  but  I  have  always  given  four  months 
as  the  Dmthnum  period,  and  doubt  whether  even  this  is  quite 
sufficient.  No  harm  is  done  if  the  patient  continues  some 
quinine  for  six  months. 

With  regard  to  the  different  preparations  of  quinine,  much 
more  strict  work  by  enumerative  methods  on  the  effect  of  the 
various  salts  on  the  parasites  is  required.  Estimations  of  the 
amounts  excreted  in  the  urine  and  so  on  give  but  partial 
information  on  the  germicidal  action — which  is  the  point  of 
importance. 

The  more  soluble  salts — bisulphate,  bihydrochloride,  hydro- 
bromide — are  most  easily  absorbed,  and  appear  most  quickly 
in  the  urine. 

The  less  soluble  salts — sulphate,  citrate,  tannate,  euquinine — 
are  absorbed  much  more  slowly,  but,  finally,  in  just  as  much 
quantity. 

Exact  enumerative  experiments  are  therefore  required  to 
decide  which  of  these  groups  of  salts  have  the  most  germicidal 
action. 

Much  has  been  said  recently  in  favour  of  the  tannate, 
e.g.  by  Nardelli  [1909]  and  Deaderick  [1909].^  It  seems  to  be 
slowly  but  largely  absorbed  ;  it  remains  in  the  blood  ;  it  is 
inexpensive,  nearly  tasteless  and  very  suitable  for  prophylactic 
use  by  children  (section  36). 

Methylene  Blue  ■  was   suggested    for   malaria  by  Guttmann 

1  AndCeIli[i9io]. 


24]  SUMMARY  143 

and  Ehrlich  [1891],  and  has  been  studied  by  Thayer  [1892], 
De  Blasi  [1902],  Wood  [1905],  Ruge  [1906]  and  others. 
Atoxyl  has  been  recently  tried  by  Koch,  Grosch  [1907] 
and  various  Greek  observers.  The  general  conclusion  is  that 
it  does  reduce  the  sporids  to  some  extent,  but  not  so  well  as 
quinine.  The  investigations  must  be  revised  and  extended. 
The  methylene  blue  must  be  pure,  and  should  be  given  in 
coated  pills  or  capsules  up  to  i  gram  or  more  a  day ;  the 
atoxyl  may  be  given  by  injection  up  to  o'2  grams  twice 
a  week.  These  and  other  drugs  are  not  yet  of  importance 
for  preventive  purposes. 

24.  Summary. — The  doctrine  of  the  parasite  invasion 
given  above  may  be  summarised  as  follows : — 

The  infecting  Anopheline  probably  injects  at  a  single 
feeding  from  a  few  to  several  thousand  protospores  of  one 
or  more  species  of  Plasmodium. 

Many  of  the  injected  protospores  probably  perish  ;  but  the 
survivors  enter  haematids  and  begin  to  multiply  at  an  average  rate 
depending  upon  their  species  and,  possibly,  certain  other  factors. 

When  the  number  of  parasites  reaches  something  like 
50  per  c.mm.  of  blood  the  patient  begins  for  the  first  time  to 
have  definite  symptoms  of  illness. 

About  the  same  time  some  kind  of  germicidal  power  which 
opposes  the  invasion  begins  to  come  into  play,  and  tends,  in 
the  great  majority  of  cases,  to  limit  the  number  of  parasites 
below  a  fatal  number. 

At  the  same  time  some  increasing  antitoxic  power  tends  to 
reduce  their  effect  upon  the  host. 

The  further  history  of  the  invasion  is  probably  that  of  a 
constant  struggle  between  the  parasites  and  the  germicidal 
power,  tending,  in  the  great  majority  of  the  cases,  to  the 
final  victory  of  the  latter. 

In  untreated  or  non-immune  cases,  this  struggle  generally 


144  THE   PARASITIC   INVASION    IN   MAN         [Sect.  24 

produces  a  long  series  of  relapses,  which  tend  to  be  precipitated 
by  many  secondary  influences  acting  on  the  host. 

Finally,  after  this  series  of  rallies  and  relapses  the  patient 
appears  often  to  reach  a  stage  of  partial  (or  ?  complete)  immunity. 

Possibly,  if  reinfection  does  not  take  place,  something  like 
half  the  cases  tend  to  recover  spontaneously  every  three  months. 

The  effect  of  reinfections  upon  the  severity  or  duration  of 
the  case  has  not  been  estimated. 

The  case  may  be  cut  short  at  any  time  by  death, 
spontaneous  recovery,  or  quinine. 

There  is  no  reason  why  we  should  suppose  that  the  infec- 
tion is  maintained  by  encystment  or  parthenogenesis  or  other 
special  arrangements  of  the  parasites,  and  the  existence  of 
such  phenomena  has  not  been  proved. 

This  doctrine  can  scarcely  be  verified  by  the  continuous 
study  of  entire  cases,  and  is  therefore  based  rather  on  the 
comparison  of  different  periods  in  the  history  of  many  different 
cases,  and  on  reasoning  from  numerous  data.^ 

The  careful  student  of  the  literature  of  the  pathology  of 
malaria  will  be  struck  by  the  immense  amount  of  admirable 
work  done  on  the  subject.  Ideas  of  number  and  quantity, 
however,  are  often  completely  disregarded — a  common  fault  of 
biological  work — with  the  result  that  many  of  the  secondary 
theories  and  explanations  will  require  to  be  examined  over  again 
by  more  laborious,  enumerative  and  quantitative  methods.- 

^  I  have  held  it,  in  the  absence  of  a  better  doctrine,  since  1895,  and  have  always 
taught  it  in  my  lectures  and  publications. 
"  See  section  65. 


CHAPTER   V 

MALARIA   IN   THE    COMMUNITY 

25.  Is  the  Infection  caused  otherwise  than  by  Anophelines.— 

Having  considered  the  parasitic  invasion  of  the  individual,  we 
must  next  examine  that  of  the  community. 

It  was  shown  in  sections  i6  and  17  that  infection  is  produced 
by  the  bite  of  certain  mosquitos ;  but  after  proof  of  this  was 
obtained,  several  capable  students  of  malaria  expressed  a  doubt 
as  to  whether  this  is  the  only  route  of  infection.  We  can 
scarcely  wonder,  then,  if  the  general  public  sometimes  have 
similar  doubts,  and  the  Health  Officer  must  be  always  prepared 
to  discuss  the  matter  fully  in  public.  The  following  questions 
are  easily  answered  : — 

( I ).  Do  mosquitos  exist  where  there  is  no  malaria  ? — They 
do ;  but  this  has  no  application  to  the  subject,  as  only  certain 
species  carry  malaria. 

(2).  Does  malarial  fever  occur  where  there  are  no  mosquitos? 
— Very  frequently,  as  on  board  ship  in  mid-ocean,  on  high 
mountains,  or  in  Britain  in  the  middle  of  winter;  but  such 
cases  are  always  relapses. 

(3).  Do  Anophelines  exist  where  there  is  no  endemic  malaria  ? 
— In  many  places,  as  in  Britain ;  but  the  presence  of  infected 
persons,  as  well  as  of  carriers,  is  required,  and,  moreover,  both 
must  be  in  sufficient  numbers  (section  28). 

(4).  Does  endemic  malaria  occur  where  there  are  no  Ano- 
phelines?— No  case  of  this  has  yet  been  established.  So  far 
as  we  know,  Anophelines  exist  in  all  warm  countries,  and  in 
most  temperate  climates  during  the  summer. 

145  K 


146  MALARIA   IN   THE   COMMUNITY  [Sect. 

But  the  Anophelines  are  often  difficult  to  find.  Thus,  I 
had  been  working  on  the  mosquito  theory  of  malaria  for  two 
years  before  I  noticed  this  group  of  gnats.  Duggan  [1897] 
said  that  there  were  few  mosquitos  in  Freetown,  Sierra  Leone, 
but  we  found  numbers  there  two  years  later.  In  1901  I 
observed  none  flying  about  in  a  new  house  at  Ibadan,  Lagos, 
West  Africa  ;  but  five  or  six,  mostly  Anophelines,  were  captured 
two  nights  in  succession  within  an  old  mosquito  -  net  with 
holes  in  it,  in  which  a  servant  slept.  If  so  many  had  been 
able  to  enter  through  the  holes  during  the  night,  how  many 
(though  none  were  observed)  must  have  been  flying  about  free  ? 
They  abound  in  Britain,  though  the  general  public  scarcely 
ever  notices  them.  Before  the  presence  of  Anophelines  in  any 
locality  can  be  denied,  a  trained  observer  must  be  employed 
to  search  for  them.  Many  workers  have  made  similar  notes 
on  this  point. 

It  does  not  follow,  because  the  insects  are  scarce  in  a  locality 
at  the  moment  when  we  visit  it,  that  they  do  not  abound  in 
it  at  some  other  season. 

(5).  Is  it  possible  to  become  infected  in  uninhabited  localities  ? 
— Some  people,  such  as  several  sportsmen  and  travellers  I  have 
met,  have  stated  that  they  acquired  malaria  in  such  places. 
One  told  me  that  he  had  frequently  been  attacked  a  few 
hours  after  entering  a  certain  big-game  district.  We  ask  in 
reply  {a)  what  about  the  incubation  period  ;  {b)  whether  the 
traveller  was  unaccompanied  by  servants  ;  and  (c)  whether  he 
had  travelled  in  a  balloon  ?  We  must  obviously  pass  through 
many  inhabited  places,  where  the  risks  of  infection  may  be 
great,  before  reaching  the  wilderness  ;  we  must  have  servants 
and  carriers  with  us ;  and  we  may  indeed  have  had  the  parasites 
in  our  own  blood,  without  knowing  it. 

(6).  If  mosquitos  become  infected  froin  men  and  m.en  from, 
mosquitos,  how  and  when  did  the  process  first  commence  ? — This 
question  is  always  asked  by  the  most  intelligent  person  present ; 
and   I   only  wish   that  we   knew  the  answer.     It  is  concerned 


25]  INFECTION    FROM   THE   SOIL  147 

with  the  whole  subject  of  the  evokition  of  metaxenous  parasites. 
Leukart  supposes,  of  course,  that  they  were  once  free  Hving 
organisms,  which  acquired  the  habit  of  Hving  first  in  one  host 
and  then,  for  greater  security  during  the  necessary  period  of 
migration,  in  another;  and  Grassi,  and  A.  J.  Chalmers  [1902] 
have  tried  to  fit  this  hypothesis  to  the  case  of  malaria.  But 
there  are  certain  grave  difficulties,  and  for  the  present  it  is 
sufficient  to  note  that,  we  must  be  satisfied  with  the  facts  as 
we  find  them. 

(7).  Has  it  been  absolutely  proved  that  malaria  does  not  come 
from  the  soil? — It  is  always  very  difficult  to  prove  a  negative 
hypothesis  of  this  kind.  We  never  know  what  surprise  Nature 
does  not  keep  in  store  for  us ;  we  are  not  omniscient,  and 
wonderful  things  happen.  But  the  fact  that  we  cannot  prove 
that  malaria  does  not  come  from  the  soil  is  no  proof  of  the 
hypothesis  that  it  does  do  so.  We  are  not  sure  that  elephants 
do  not  exist  in  the  moon  ;  but  our  ignorance  here  does  not 
prove  that  they  do  exist  there.  Malaria  may  just  possibly 
rise  from  the  soil ;  but  there  is  no  evidence  at  all  that  it  does 
so.  In  my  experience,  those  who  argue  in  favour  of  this 
speculation  nearly  always  confound  relapses  with  original 
infections.  True,  we  occasionally  meet  with  cases  which  are 
not  easy  to  explain  on  the  mosquito  theory,  but  I  have 
never  met  one  which  could  not  possibly  be  explained  by  it. 

On  the  other  hand,  there  are  many  strong,  very  strong, 
arguments  against  the  idea  that  malaria  is  bred  directly  in  the 
soil  or  in  the  marsh.  In  the  first  place,  all  experiments  to  infect 
men  with  air  or  water  brought  from  malarious  localities  have 
failed  (section  17).  Secondly,  if  malaria  were  due  to  any 
particular  kind  of  soil  under  certain  conditions  (as  has  been 
supposed),  it  should  always  be  present  where  that  soil  and 
those  conditions  exist.  But  we  know  that  actually  it  comes 
and  goes.  For  example,  it  came  to  Mauritius  in  1866,  and 
to  Reunion  in  1867 ;  it  is  still  absent  from  Seychelles  and 
Rodrigues,  though   favourable  conditions  for  it  exist  in  those 


148  MALARIA    IN    THE   COMMUNITY  [Sect. 

islands,  and  it  has  disappeared  from  Great  Britain.  But  the 
soil  and  the  climate  of  these  areas  have  not  changed.  Thirdly, 
if  the  poison  is  diffused  in  the  air  it  ought  to  affect  every  one 
within  a  considerable  area  round  the  generating  centre,  but 
as  a  rule  the  disease  is  limited  to  the  immediate  vicinity  of 
the  marsh.  Fourthly,  the  telluric  miasm  ought  to  attack 
especially  those  who  are  engaged  in  digging,  but  I  have  never 
obsened  that  cultivators  and  gardeners  suffer  much  more  than 
their  neighbours ;  while,  as  a  matter  of  fact,  it  is  generally 
the  children  and  even  the  infants  who  suffer  the  most.  Lastly, 
the  idea  that  the  parasites  can  live  in  soil,  water  and  air,  as 
well  as  in  men  and  mosquitos,  is  extremely  improbable  in  the 
light  of  our  general  knowledge  of  parasites. 

The  last  is  probably  the  clinching  argument.  Living 
organisms  do  not  possess  independent  properties,  but  accord 
more  or  less  in  their  structure,  capacities,  habits  and  life-history 
with  other  organisms.  We  are  cognisant  of  thousands  of 
parasites  of  men,  animals  and  plants  ;  and  what  we  know  of 
the  parasites  of  malaria  shows  that  they  are  not  markedly 
exceptional.  In  fact  they  belong  to  a  class  of  parasites  which 
infect  two  hosts,  one  of  which  feeds  on  the  other — as,  for 
instance,  {>arasites  of  the  deer  and  the  tiger,  the  mouse  and 
the  cat,  the  ox  and  man,  the  ox  and  the  cattle  tick,  and  now 
man  and  mosquitos.  The  general  law  is,  therefore,  satisfied 
by  the  known  life-histor)-  of  malaria.  We  have  no  reason  to 
expect  another  life-history  for  the  malaria  parasites  in  soil, 
water  or  air,  any  more  than  for  the  other  parasites.  Then 
again,  every  animal  possesses  only  the  limited  p>owers  which 
have  been  given  to  it  by  the  evolution  of  ages,  and  for  which 
it  has  acquired  definite  organs  and  habits  of  life.  The  mole 
burrows,  the  fish  swims,  the  bird  flies,  the  parasite  occupies 
the  higher  animal  or  plant  But  if  this  telluric  h\pothesis  is 
sound,  what  remarkable  animals  must  these  parasites  of  malaria 
be !  They  already  possess  a  structure  wonderfully  adapted 
for  their  life  in  men  and  also  in  mosquitos ;   but  we  must  now 


25l  OTHER   CARRIERS  149 

expect  that  they  are  also  able  to  burrow  like  the  mole,  swim 
like  the  fish,  and  fly  like  the  bird  !  To  do  all  these  things  they 
must  have  the  suitable  organs ;  and  not  only  this,  but  they  or 
their  spores  must  be  protected  against  heat  and  cold  and  hosts 
of  enemies  in  soil,  water  and  air.  If  all  this  were  true  we 
should  have  to  put  the  parasites  of  malaria  in  a  special  class 
by  themselves,  apart  from  the  rest  of  creation. 

These  reasons  have  now  led  pathologists  and  parasitologists 
(who  can  perhaps  appreciate  their  weight  better  than  others) 
to  abandon  the  telluric  hypothesis  as  a  likely  one.  There  is 
no  evidence  in  favour  of  it,  and  there  are  very  strong  arguments 
against  it.  The  true  theorem  is  obvious.  The  connection 
between  malaria  and  the  marsh,  so  long  known  to  suffering 
humanity,  is  now  fully  explained  by  the  fact  that  the  Anophelines 
breed  in  the  marsh.  There  is  no  necessity  to  believe  that  the 
germs  also  breed  in  the  marsh.  Malaria  comes  from  the  marsh, 
not  because  the  germs  of  the  disease  come  from  it,  but  because 
the  carriers  of  the  germs  do  so.  It  is  the  same  thing  in  the 
end.  The  ancient  theory  was  quite  right.  Malaria  is  caused  by 
a  marsh  miasm.  The  Anophelines  themselves,  the  mosquitos, 
are  the  marsh  miasm. 

(8).  Do  other  insects  besides  Anophelines  carry  malaria  ? — 
First  we  should  note  that  not  all,  but  only  certain  species  of 
Anophelines  carry  it,  and  that  according  to  some,  only  certain 
varieties  of  some  of  these  species  are  effective.  As  a  fairly 
general  rule,  animal  parasites  are  very  particular  in  their 
choice  of  hosts.  Thus  no  one  has  succeeded  in  infecting 
animals  with  human  malaria,  and  the  probability  is  that  it  will 
not  exist  in  many  kinds  of  mosquitos.  Between  1895  and  1899 
I  failed  entirely  in  infecting  several  species  of  Culex  and 
Stegomyia,  though  I  made  experiments  on  hundreds  of  the 
insects ;  and  these  results  were  confirmed  by  the  Italian 
observers,  by  Stephens  and  Christophers,  and  by  many  others. 
But,  nevertheless,  such  negative  results  are  never  absolutely 
conclusive  unless  enormous  numbers  of  experiments  are  made, 


ISO  MALARIA   IN   THE   COMMUNITY  [Sect. 

because  it  is  always  possible  that  some  condition  such  as  of 
temperature  or  humidity  may  have  been  overlooked,  or  that 
the  proper  species  or  variety  may  not  have  been  used.  But 
there  is  a  strong  argument  against  mosquitos  in  general  being 
concerned,  namely,  that  from  the  oldest  times  malaria  has 
been  known  to  be  connected  with  marshes,  while  many 
mosquitos,  such  as  most  Culex  and  Stegojnyia,  do  not  breed 
in  marshes  as  a  rule,  but  in  petty  collections  of  water  round 
houses.  If  these  carry  malaria,  then  malaria  should  abound 
everywhere,  especially  in  towns,  and  not  so  exclusively  near 
marshes.  A  good  contrast  is  found  in  the  case  of  yellow  fever, 
which  does  abound  in  towns  and  not  particularly  near  marshes 
— for  the  simple  reason  that  it  is  carried  by  Stegomyia. 

On  the  whole,  then,  though  we  cannot  say  definitely  that 
malaria  is  not  carried  by  other  hosts  than  Anophelines,  yet 
there  are  strong  reasons  for  this  opinion.  At  all  events  we  are 
fairly  certain  that  most  insects  which  carry  it  must  be  marsh- 
born,  like  the  Anophelines ;  so  that  the  principal  preventive 
measure  of  drainage  is  not  seriously  affected  by  the  question. 

(9).  Do  the  human  parasites  live  also  in  animals? — In  1898 
in  Calcutta,  my  servant,  Mahomed  Bux,  became,  suddenly 
infected  with  malaria,  which  he  thought  he  had  acquired  while 
collecting  mosquitos  fed  on  infected  birds.  At  present,  how- 
ever, no  one  thinks  that  the  parasites  of  men  and  of  animals 
are  the  same.  The  attempts  of  Di  Mattel  and  others  to  infect 
birds  from  men  were  all  negative. 

( I  o).  Do  the  parasites  enter  the  eggs  and  larvae  of  mosquitos  ? — 
In  1898  also,  I  thought  that  the  protospores  of  P.  danilevskyi 
might  enter  the  eggs  of  the  carrying  mosquitos,  but  all  my 
attempts  to  find  them  there  were  failures.  More  recently 
Schaudinn  [1904]  has  sought  to  revive  this  hypothesis  ;  but  he 
gave  no  proof  of  it.  Such  a  thing  happens,  however,  with 
Piroplasma  in  ticks,  and  has  been  suggested  as  possible  in  the 
case  of  yellow-fever.  If  it  happens  in  malaria,  the  parasites 
would  be  passed  on,  not  only  from  mosquito  to  man,  but  also 


26]  DEFINITIONS  151 

from  mosquito  to  mosquito.  I  have  had  no  opportunities  for 
examining  the  subject  further,  but  may  add  that  my  studies  on 
the  point  in  1898  were  very  careful.  We  should  not  accept  the 
suggestion,  even  tentatively,  without  much  better  evidence. 

26.  Some  Definitions. — We  are  therefore  almost  sure  that 
infection  with  the  parasites  of  malaria  occurs  in  nature  only 
through  the  bites  of  mosquitos  —  probably  only  of  certain 
species  of  Anophelines.  But  this  statement  is  not  nearly 
sufficient  for  all  the  purposes  of  prevention,  and  we  must 
discuss  the  subject  in  much  greater  detail.  Why  does  the 
disease  vary  in  amount  from  place  to  place,  or  even  in  the 
same  place  from  season  to  season,  or  year  to  year  ?  Why  does 
it  disappear  from  some  countries  and  appear  in  others?  The 
whole  subject  of  the  prevention  of  malaria  is  based  upon  a 
rational  study  of  these  questions,  and  the  reader  who  is  called 
upon  to  undertake  such  work  must  exert  himself  to  consider 
them  thoroughly.  We  must  first  have  clear  ideas  upon  the 
following  points : — 

(i).  The  cases  of  malarial  fever  which  occur  within  a 
given  locality  belong,  of  course,  to  two  classes,  the 
indigenous  cases  and  the  imported  cases.  The  first 
are  those  who  were  infected  within  the  locality ; 
the  latter,  those  who  were  infected  outside  it,  but 
who,  after  immigration,  remain  infected  within  it. 
The  latter  class  may  be  very  numerous  in  military 
stations,  hill  stations,  and  sanatoria.  But  they  also 
abound  in  many  villages  of  which  the  inhabitants 
are  given  to  working  elsewhere  during  the  malarious 
months ;  and  among  bands  of  immigrant  workmen. 
On  the  other  hand,  in  small  towns  and  villages  with 
fixed  populations  most  of  the  cases  are  apt  to  be 
indigenous  ones.  It  is  often  difficult  to  determine 
the  proportion  of  each  class  because  many  of  the 
imported  cases   may  be  reinfected  within  the  area 


152  MALARIA   IN   THE   COMMUNITY  [Sect. 

of  observation,  while  many  of  the  indigenous  cases 

may  have  emigrated  since  infection. 

(2).  By  the  malaria  rate  of  a  locaHty  I  mean  the  percentage 

of  persons  who  contain   plasmodia  at  some  given 

moment.     We  may  divide  this  into  the  indigenous 

malaria  rate  and   the  imported  malaria  rate.     The 

former  may  also  be  called  the  malarial  endemicity  of 

the  place. 

(3).  By  the  malaria  index,  or  endemic  index,  of  a  locaHty 

I    mean    the    percentage   of  persons  in  whom   any 

evidence   of  malarial    infection    was  found  at  some 

given   moment.     It  will  be  clear  from  Chapter  IV 

that   such    evidence  cannot  generally  be    found  in 

all  the  cases  of  malaria  in  a  locality — many  may 

contain    plasmodia   without   showing   them  or  any 

objective   symptoms   of  them.      Conversely,   many 

people  may  show  evidence  of  past  infection,  such 

as   enlarged   spleen,  without    containing  plasmodia 

at  the  moment.      We  may  divide  the  endemic  (or 

malaria)  index  into  the  adult,  the  juvenile  and  the 

infantile  endemic  index} 

(4).  By  the  daily,  monthly  or  annual   inoculation  rate  of 

a  locality  I   mean  the  percentage  of  persons  who 

were  inoculated  or  reinoculated  by  mosquitos  during 

the  day,  month  or  year  referred  to. 

(5).  When  we  talk  of  the  amount  of  malarial  fever  in  a 

locality  we  generally  refer  to  the  total  malaria  rate 

in  it.     When  we  talk  of  the  amount  of  malaria  in 

it  we  generally  mean  its  indigenous   malaria  rate. 

When  we  say    that   a   place   or   a   season    is    very 

malarious,  we  mean  that  the  inoculation  rate  is  very 

high  for  that  place  or  season. 

1  The  term  "  endemic  index  "  was  first  used  by  Stephens  and  Christophers  to  denote 
the  percentage  of  children  showing  the  parasites  in  the  blood,  but  the  above 
definition  is  more  correct. 


27]  CONDITIONS   OF    INFECTION  153 

(6).  By  the  malarial  case  mortality  we  mean,  of  course,  the 
proportion  of  infected  persons  who  die  of  the  disease. 

(7).  By  the  malarial  mortality  we  mean  the  proportion  of 
the  total  population  who  die  of  the  disease. 

(8).  I  use  the  word  ratio  to  denote  a  proportion,  and  the 
word  rate  to  denote  a  percentage.  The  latter  is 
obtained  by  multiplying  the  former  by  one  hundred. 

27.  Conditions  required  for  the  Production  of  New 
Infections  in  a  Locality. — From  what  has  been  written  already 
it  will  appear  that  new  infections  can  occur  in  a  locality  only 
if  all  the  following  conditions  exist : — 

(i).  That  a  person  whose  blood  contains  a  sufiflcient  number 
of  gametids  (sexual  forms)  is  living  in  or  near  the 
locality. 
(2).  That  an  Anopheline  capable  of  carrying  the  parasites 

sucks  enough  of  that  person's  blood. 
(3).  That  this  Anopheline  lives  for  a  week  or  more  after- 
wards  under   suitable   conditions — long   enough  to 
allow  the  parasites  to  mature  in  it. 
(4).  That  it  next  succeeds  in  biting  another  person  who  is 
not  immune  against  the  disease  or  is  not  protected 
by  quinine. 
To  these  we  must  now  add  the  following  principle  : — 
(5).  That  few  or  no   new  infections  will  occur  in  a  com- 
munity  unless   the   persons   with   gametids  in   their 
blood  and  the  carrying  Anophelines  are  sufficiently 
numerous. 
This  last  proposition  is  the  basis  of  the  public  prevention 
of  malaria.      Although  tacitly  admitted,  it  is    never   properly 
discussed    in  the  monographs,  and   the  reader   must  therefore 
examine  it  here  in  detail  and  as  precisely  as  possible. 

Let  us  suppose  that  we  have  to  do  with  a  population  of 
1,000  people  living  over  an  area  in  which  indigenous  malaria 
does   not  exist ;    and  suppose  that  one  of  these  people  is  an 


154  MALARIA   IN   THE  COMMUNITY  [Sect. 

imported  case  with  suitable  gametids  in  his  blood.  Next, 
suppose  that  a  single  suitable  Anopheline  is  liberated  within 
the  area.  What  are  the  chances  that  this  insect  will  ever  cause 
a  new  infection  ? 

First,  we  observe  that  not  every  mosquito  can  succeed  in 
biting  human  beings  at  all :  suppose  that  the  chances  are 
4  to  I  against  this  happening.  Next,  we  observe  that  as  there 
is  only  one  infected  person  among  the  i,ooo  people  in  the  place, 
and  as  the  particular  Anopheline  liberated  in  the  area  may 
bite  any  one  of  these  people,  the  chances  are  i,ooo  to  i  against 
its  happening  to  bite  the  patient,  even  if  it  succeeds  in  biting 
at  all.  That  is,  altogether,  the  chances  against  its  biting  the 
patient  are  4,000  to  i.  But  suppose  that  this  has  happened. 
It  must  now  live  for  a  week  or  more  afterwards,  and  not  all 
mosquitos  live  so  long.  Suppose  that  the  chances  are  3  to  i 
against  this  particular  Anopheline  living  long  enough  to  mature 
the  parasites  in  it — so  that  the  chances  are  12,000  to  i  against 
the  Anopheline  reaching  the  infective  stage.  But  it  must  now 
bite  a  second  person.  Suppose  that  the  chances  against  this 
are,  again,  4  to  i.  Thus  the  total  chances  against  this 
Anopheline  inoculating  another  person  will  be  something  like 
48,000  to  I.  In  other  words,  if  instead  of  liberating  a  single 
Anopheline  within  the  area  of  observation  we  had  liberated 
48,000,  the  chances  are  that  only  one  of  these  would  succeed 
in  biting  the  patient,  and  would  also  live  long  enough  to  become 
infective  and  to  bite  a  second  person.  Of  course,  by  bad  luck, 
so  to  speak,  a  larger  proportion  of  the  insects  might  succeed 
in  this  ;  but,  on  the  other  hand,  by  good  luck,  none  at  all  might 
succeed.  Such  calculations,  though  obviously  based  on  con- 
jectural data,  yet  suffice  to  show  the  absurdity  of  supposing 
that  the  presence  of  a  few  Anophelines  must  cause  an  epidemic 
of  malaria. 

Or  we  may  consider  the  subject  as  follows  : — Suppose  that 
48  Anophelines  on  the  average  live  near  the  infected  person. 
Then,  if  the  conjectural  data  are  sound,   1/4  of  these,  or  12, 


27]  CONDITIONS   OF    INFECTION  155 

will  succeed  in  biting  him  ;  1/3  of  these,  or  4,  will  live  for  a 
week  or  more  ;  and  only  1/4  of  these,  or  i,  will  succeed  in  biting 
another  person.  If  48  Anophelines  live  near  each  one  of  the 
999  healthy  people,  there  will  be  47,952  Anophelines"  which 
can  bite  only  healthy  people,  and  which  cannot  therefore  cause 
new  infections.  Thus,  on  the  average,  only  i  out  of  48,000 
Anophelines  will  succeed  in  infecting  another  individual. 

If  instead  of  only  one  person  with  gametids  in  the  blood 
there  are  2,  3,  4  ...  or  more  in  the  locality,  then  if  there  are 
48  Anophelines  on  the  average  to  each  person,  2,  3,  4  ...  or 
more  new  infections  may  be  caused.  Thus,  obviously,  the 
number  of  new  infections  in  a  locality,  that  is,  the  inoculation 
rate,  depends  on  two  factors  (other  things  being  equal),  namely, 
the  number  of  Anophelines  and  the  number  of  previously 
infected  persons  in  the  locality. 

It  is  useful  to  put  these  thoughts  into  simple  symbolic 
language.  Let/  denote  the  human  population  of  the  locality  ; 
nip  the  number  of  malaria  -  infected  persons ;  and  imp  the 
number  of  these  with  gametids  in  the  blood.  Here  vi  and  / 
are  fractions,  since  7np  is  less  than  /,  and  imp  less  than  mp. 
Also  m  may  vary  from  o  to  i,  since  the  number  of  infected 
persons  may  be  anything  from  zero  to  the  whole  population. 
The  fraction  i,  being  the  proportion  of  infected  persons  with 
gametids  in  their  blood  at  the  moment  of  enquiry,  may  be 
put  at  1/4,  or  may  be  much  less. 

Again,  let  a  denote  the  number  of  Anophelines  (of  some 
malaria  -  bearing  species)  to  each  human  being  —  so  that  ap 
denotes  the  total  number  of  Anophelines  in  the  locality,  and 
aimp  the  number  of  Anophelines  compared  with  the  number 
of  persons  with  gametids.  Let  b  be  the  proportion  of  these 
(say  1/4)  which  succeed  in  biting ;  s  the  proportion  (say  1/3) 
which  succeed  in  maturing  the  parasites  ;  and  b  the  proportion 
which  succeed  in  biting  another  person.  Then  bsbaimp  gives 
the  number  of  Anophelines  which  succeed  in  infecting  persons. 


156  MALARIA   IN   THE   COMMUNITY  [Sect. 

We  have  assumed  that  b^ij^,  •$'=i/3.  2=  1/4;  so  that  if  each 
of  these  bites  a  different  person,  we  shall  have — 
No.  of  \noc\x\2A.\ons  =  b'^saiinp  =  amp  I  ig2 

Inoculation  rate  %  =  — ^-   •  —  =  about  h  am. 
'°     192         p 

That  is  to  say,  the  inoculation  rate  per  icx)  of  population  equals 

about  half  the  malaria  ratio  (w)  multiplied  by  the  mosquito 

ratio  {a). 

For  example,  in  a  village  containing  1,250  people,  750 
infected  people,  and  3,000  Anophelines,/'=  1,250,  m  =  o-b,  rt  =  2"4; 
and  we  calculate  roughly  that  the  number  of  infecting  Anophe- 
lines,  and  also  of  inoculations,  will  be  about  9*4.  The  inoculation 
rate  per  cent,  will  be  about  1/2  (2*4XO"6)  =  o72  ;  that  is,  the 
chances  of  being  inoculated  in  the  village  will  be  as  72  is 
to  10,000. 

Or  suppose  that  in  another  village  half  the  people  are  in- 
fected, and  there  are  about  twenty  Anophelines  to  each  person. 
Then  the  chances  of  becoming  infected  there  will  be  about  5/100. 

Such  calculations  may  appear  far  -  fetched  to  many ;  but 
they  are  useful,  not  so  much  for  the  numerical  estimates  yielded 
by  them,  but  because  they  give  more  precision  to  our  ideas, 
and  a  guide  for  future  investigations. 

28.  Laws  which  Regfulate  the  Amount  of  Malaria  in  a 
Locality. — The  number  of  infecting  mosquitos  which  succeed 
in  biting  again  is  b^saiinp.  If  all  of  these  bite  different  people, 
and  all  these  people  are  healthy,  and  all  become  infected,  this 
expression  will  also  denote  the  number  oinew  infections  occurring 
in  the  locality.  But,  of  course,  the  infecting  mosquitos  may 
often  happen  to  bite  on  the  second  occasion,  not  healthy 
persons,  but  persons  already  infected,  especially  if  the  pro- 
portion of  the  latter  is  large. 

If,  as  before,  mp  denotes  the  number  of  persons  already 
infected  at  the  beginning  of  the  enquiry,  then/  —  ?;//  or  (i  —m)p 
denotes  the  number  of  healthy  people.     Hence  by  proportion 


28]  LAWS   OF   DIFFUSION  157 

the  number  of  infecting  mosquitos  which  bite  healthy  persons 
(on  the  second  biting)  will  be  x,  where 

X  :  U^saimp  ::  {i—m)p  : p 

or  X  =  b'^sai  {i  —  m)  mp     .         .         .         .         (i) 

and  if  each  bites  a  different  person  and  each  person  becomes 
infected,  the  same  expression  will  denote  the  number  of  new 
infections  which  occur  in  the  locality — that  is,  will  denote  the 
addition  to  the  number  of  malaria  cases  there. 

But  this  is  not  the  whole  change  which  may  occur.  While, 
during  the  period  of  observation,  new  infections  are  being  pro- 
duced, it  may  happen  that  some  of  the  old  cases  may  have 
recovered.  The  number  of  those  old  cases  was  originally  mp : 
let  rmp  denote  the  number  of  those  who  have  recovered  during 
the  period  of  observation — so  that  r  is  a  fraction.  Hence  the 
whole  number  of  cases  in  the  locality  will  have  increased  or 
decreased  at  the  end  of  the  period  of  observation,  according 
to  whether  b'^sai  (i  — ;;/)  mp,  the  number  of  new  cases,  is  greater 
or  less  than  rmp,  the  number  of  recoveries.  Thus  (neglecting 
common  factors)  the  change  depends  upon  whether  b-sai  {\  —in) 
is  greater  or  less  than  r. 

Suppose  that  no  change  occurs — that  the  recoveries  exactly 
equal  the  new  infections.     Then 

b'^saz  {i—in)  =  r  ....  (2) 
From  this  equation  we  can  calculate  the  values  of  a  and  m 
when  the  amount  of  malaria  in  the  locality  remains  constant — 
that  is,  if  we  know  the  values  of  b,  s,  z,  and  r. 

Suppose  that  the  period  of  observation  is  one  month.  Now, 
in  section  21,  I  estimated  roughly  that  only  about  half  the  cases 
of  malaria  remain  infected  after  three  months.  If  this  rate 
holds  for  smaller  periods,  we  may  suppose  that  the  ratio  of 
people  who  remain  infected  after  only  one  month  will  be  given 
by  the  cube  root  of  1/2 — that  is,  by  07937  ;  so  that  the  pro- 
portion of  those  who  recover  in  one  month  will  be  1—07937. 
That  is,  we  may  write  r  =  0*2062.  Let  us  take  the  values  of 
b,  s,  t  as  suggested  in  the  previous  section — so  that  b-si=  1/192. 


158  MALARIA   IN   THE   COMMUNITY  [Sect. 

Hence    the    new    infections    will    equal    the    recoveries    if 

a{i- m)  =  192  X 0-2062  =  39-59  =  40  {say)  ...  (3) 
and  the  malaria  will  increase  or  diminish  in  the  locality  accord- 
ing to  whether  a{\  —in)  is  greater  or  less  than  40.  Thus,  if  in, 
the  original  malaria  rate,  is  very  small,  the  malaria  will  not 
increase  unless  a,  the  monthly  number  of  Anophelines  per  head 
of  human  population,  is  greater  than  40.  On  the  other  hand, 
if  ;;;  is  a  larger  fraction,  say  1/2,  the  malaria  will  not  increase 
unless  a  is  greater  than  80.  If  in  is  still  larger,  say  3/4,  the 
malaria  will  not  increase  unless  a  is  greater  than  160.  This 
suggests  that  the  malaria  rate  is  not  likely  to  increase 
indefinitely  unless  the  number  of  mosquitos  is  enormous.  On 
the  other  hand,  if  the  number  of  Anophelines  is  below  the 
figure  given  by  the  equation,  the  malaria  rate  ought  to  begin 
to  fall,  because  the  new  infections  can  no  longer  keep  pace  with 
the  recoveries. 

It  should  be  noted  that  by  the  number  of  Anophelines  we 
here  mean  the  number  of  different  Anophelines  which  may  bite 
each  person  during  a  whole  month,  and  not  the  insects  which 
may  be,  so  to  speak,  allotted  to  each  person  at  any  one  moment. 
We  say  one  month  because  this  is  the  period  we  have  selected 
for  observation  —  the  period  during  which  we  suppose  that 
0*2  or  I /5th  of  the  cases  recover.  If  we  had  selected  one  week 
for  the  period  of  observation,  the  proportion  of  recoveries  would, 
of  course,  be  lower  (about  0*056 142),  and  the  number  of  different 
Anophelines  to  each  person,  required  to  compensate  for  the 
recoveries  during  the  week,  would  be  correspondingly  less  (as 
shown  by  the  equation). 

Now,  what  will  happen  if  the  malaria  rate,  instead  of 
remaining  constant,  increases  or  decreases  ?  On  the  one  hand, 
will  it  increase  until  every  one  becomes  infected ;  or,  on  the 
other  hand,  will  it  decrease  until  it  vanishes? 

We  have  supposed  that  inp  denotes  the  number  of  cases 
at  the  beginning  of  the  enquiry,  which  lasts,  let  us  say,  for  a 
month.     Let  ni^,  tn^ip,  w^p  ,  .  .  denote  the  number  of  cases 


28]  LAWS   OF   DIFFUSION  159 

at  the  end   of  i,  2,  3  .  .  .   months  respectively.     Then  if  the 

other  figures  remain  constant,  we  have, 

m^p  =  original  cases -\- new  infections  —  recoveries 

=  vip  +  b'^sai  ( I  —  w)  mp  —  rmp      .         .         .         .         .         (4) 

and  as  the  same  process  repeats  itself  month  after  month  we 

continue  to  have, 

m^p  =  Wj/  +  d'^sai  ( i  —  m■^)  m^p  —  rni^p 
m^p  =  m^J)  +  b'^sai  ( i  —  vi^  w^p  —  rm^J) 

and  so  on.  We  can  calculate  m^  from  the  first  equation. 
Substituting  its  value  in  the  second  equation  we  calculate  m^ ; 
and  substituting  this  in  the  third  equation  we  calculate  m.^ ; 
and  so  on  indefinitely. 

If  r=o'2  and  b^si='00%  the  value  of  the  7ith  term  of  the 
series  m^p,  m^  .  .  .  m„..,p,  m„p  may  be  written 

in „p  =  {160 -\- a  — am „..,)  m„..,px  o-oo^         •         •         •         (S) 

Let  us  now  consider  for  examples  the  case  of  a  village 
containing  1,000  people  of  whom  half  are  infected  at  the 
beginning  of  the  enquiry.  By  equation  (3)  of  this  section,  and 
also  by  this  equation,  if  the  number  of  different  Anophelines 
per  person  during  one  month  {a)  is  80,  the  malaria  will  neither 
increase  nor  decrease,  so  that  w„  will  always  be  the  same  as  w, 
namely,  0*5.  But  if  a  is  greater  or  less  than  this,  the  malaria 
will  increase  or  decrease  accordingly. 

(i).  First,  suppose  that  there  are  100  different  Anophelines 
per  person  during  a  month — so  that  the  malaria  should  increase. 
Thus  we  calculate, 

m^p  =  {i6o+  100—  iooxo"5)x  5x0*5  =  525 

W2^  =  (i6o+  100—  iooxo'525)x5xo-525  =  544'5. 

Proceeding  in  this  way  we  find  that  the  number  of  cases 
should  increase  every  month  as  follows : — 

Increase  of  Cases  with  100  Anophelines 


Months 

0 

I 

2 

3 

4 

.    finally 

Cases 

500 

525 

544 

560 

571 

600 

i6o  MALARIA   IN   THE   COMMUNITY  [Sect. 

But  how  do  we  reach  the  last  figure  ?  As  we  calculate  the 
number  of  cases  month  after  month  we  observe  that  they  always 
increase,  but  by  a  constantly  decreasing  increment.  Finally, 
this  increment  becomes  very  small,  so  that  the  number  of 
cases  approaches  a  fixed  limit.  It  is  easy  to  calculate  this 
limit  mathematically  (as  will  be  done  presently),  but  we  can 
also  calculate  it  very  simply  as  follows.  If  the  number  of  cases 
does  ever  arrive  at  a  fixed  limit,  so  that  it  no  longer  increases, 
then  equation  (3)  of  this  section  must  hold  ;  that  is,  the  number 
of  cases  and  the  number  of  mosquitos  will  be  exactly  balanced 
according  to  the  formula  a  (i— ;//)  =  40.  From  this  we  have, 
when  this  exact  balance  is  reached, 

m=\—  Afi\a (6) 

Here  <?=ioo;  so  that  finally  w=i— 0'4  =  0"6;  which,  when 
multiplied  by  the  population  (1,000),  gives  600  cases  as  the 
final  limit. 

(2).  Next,  suppose  that  there  are  only  60  Anophelines  per 
person.     Then  we  calculate  as  before, 

Decrease  of  Cases  with  60  Anophelines 


Months 

0 

I 

2 

3 

4 

-.    finally 

Cases 

500 

475 

455 

438 

424 

■      ■       333 

The  final  result  is  obtained  as  before  from  equation  (6).  Here 
then,  although  the  malaria  ratio  diminishes  rapidly  at  first,  it 
never  disappears  altogether,  but  ultimately  stands  at  1/3  of  the 
population. 

(3).  Next  suppose  that  there  are  40  Anophelines  per  person. 

Decrease  of  Cases  with  40  A  nophelines 

Months  o  I  2  3  4  .       .       .    finally 

Cases  500        450        409        376        348         ...  o 

Here  the  fall  is  quicker  and  the  malaria  finally  vanishes, 
because  ?«=  i —40/40  =  0 ;  but  very  many  months  will  elapse 
before  this  result  is  approached. 


28]  THE   LIMIT   OF   MALARIA  i6i 

(4).  We  also  have 

Decrease  of  Cases  with  i  Anopheline  per  head. 


Months 

0            I             2            3            4           .       . 

.     finally 

Cases 

500        401         322        259        207 
(5)  Decrease  of  Cases  with  no  Anophelines, 

0 

Months 

0           I           2           3           4          .      .      . 

finally 

Cases 

500        400        320        256        205 

0 

Thus  the  presence  of  only  a  small  number  of  Anophelines  does 
not  affect  the  result  very  much.  In  fact  we  can  see  this  from 
the  form  of  the  equation  (5),  namely, 

because  i  —  7;/^^  is  always  a  fraction,  and  a  must  therefore  be 
a  considerable  number  if  it  is  to  have  any  marked  effect 
compared  with  the  first  term   160. 

Returning  now  to  the  subject  of  the  limit  mentioned  in 
example  (i).  It  is  known  in  mathematics  that  if  a  series  such 
as  Wj,  w^,  W3  .  .  .  here  considered  tends  to  a  limit,  that  limit 
can  often  be  easily  found.  Let  M  denote  the  limit — that  is, 
M=in^  when  Jt,  the  number  of  terms,  is  indefinitely  increased. 
In  other  words,  M  is  the  malaria  ratio  which  is  finally  arrived 
at  after  the  lapse  of  many  months. 

Now  we  had  in  equation  (4), 

By  the  mathematical  rule  referred  to,  the  value  of  w  ,  or  M. 
can  be  easily  found,  when  n  is  large,  by  solving  the  equation 

Mp={i+bhai{\-M)-r]Mp 
that  is, 

M=i-rlb'^sai (7) 

If  ;-  =  o-2  and  b'^si=  1/200,  this  gives  7J/=  i  —40/di,  which  is  the 
same  as  equations  (2)  and  (3),  which  have  already  been  used  to 
find  the  limit  shown  in  example  (i).  There  we  calculated  the 
limit  by  another  line  of  reasoning,  but  now  we  see  that  it  can 
be  obtained  also  by  the  ordinary  mathematical  rule.  (This 
rule  is  that  if  ^";ir  is  a  repeated  function  of  x,  its  value  when  n 

L 


i62  MALARIA    IN   THE    COMMUNITY  [Sect. 

is  indefinitely  large   will   often  be    given    by  the  roots  of  the 
equation  ,r=  (px). 

The  reader  should  make  a  careful  study  of  those  ideas, 
and  will,  I  think,  have  little  difficulty  in  understanding  them, 
though  he  may  have  forgotten  most  of  his  mathematics.  If 
our  reasoning  has  been  correct  and  complete  enough,  the  main 
principles  involved  may  be  stated  as  follows : — 

(i).  Whatever  the  original  number  of  malaria  cases  in  the 
locality    may    have    been,    the    ultimate    endemic 
malaria  ratio  will   tend  to  settle  down   to   a  fixed 
figure,  dependent   on   the   number  of  Anophelines 
and    the   other   factors  —  that    is,    if  these   factors 
remain  constant  all  the  time,^ 
(2).  If  the  number  of  Anophelines  is  sufficiently  high,  the 
ultimate   malaria   ratio   (M)   will   become   fixed   at 
some    figure    between   o   and    i    (that   is,   between 
0%   and    100%).     If  the  number  of  Anophelines  is 
sufficiently    low    (say   below    40   per    person),   the 
ultimate  malaria  rate  will  tend  to  zero — that  is,  the 
disease  will  tend  to  die  out.     (In  this  calculation  a 
negative  malaria  ratio,  that  is,  one  which  is  less  than 
nothing,  must  be  interpreted  as  meaning  zero). 
Consider,  for   example,   the   case   of    a   village   with    1,000 
inhabitants    and    60    different    Anophelines    for    each    person 
during  one  month.     If,  to  begin  with,  every  person  starts  with 
being  infected,  then  the  malaria  ratio  will  fall  month  by  month 
until    it   reaches    the   value   i1/=  1—40/60;    that   is,  until    333 
persons  are  left  infected.     And  this  occurs  because  there  are 
not  enough  Anophelines  to  maintain  the  original  high  rate  of 
100%  infection.     But  now  suppose  that  with  the  same  number 
of  people  and   of  Anophelines,  the  epidemic  began  with  only 
one  infected  person  from  outside :  the  number  of  Anophelines 

1  This  is  a  well-known  peculiarity  of  repeated  functions.  See,  for  instance,  my 
paper  "A  Method  of  solving  Algebraic  Equations,"  Nature,  29th  October  1908, 
p.  663. 


28]  THE   LIMIT   OF    MALARIA  163 

will  now  be  too  large  to  allow  this  original  low  rate  of  0'i% 
infection  to  continue,  and  the  rate  will  consequently  rise  until 
the  value  M=  1—40/60,  giving  333  infected  persons,  is  reached. 
Thus,  whether  every  one,  or  only  one  person,  is  infected  to  start 
with,  the  ultimate  result  will  be  the  same — the  number  of  cases 
will  be  333,  and  will  continue  at  that  figure  so  long  as  all  the 
factors  remain  the  same.  That  is,  an  exact  balance  between  the 
number  of  cases  and  the  number  of  Anophelines  will  be  arrived 
al     Many  months  may,  however,  elapse  before  this  happens. 

Suppose  that  all  the  factors  d,  s,  z,  a,  r  do  not  remain  the 
same.  Then  if  any  of  them  is  temporarily  altered  a  correspond- 
ing change  will  be  made  in  the  rate  of  increase  or  decrease  ; 
but  after  the  temporary  disturbance  has  ceased,  things  will 
again  tend  to  return  to  the  normal  state — just  as  water  always 
seeks  to  find  its  own  level.  Thus,  if  the  recovery  rate  r  is 
increased  by  a  temporary  administration  of  quinine,  or  the 
number  of  mosquitos  a  is  temporarily  diminished  by  winter  or 
by  active  "  petrolage,"  a  change  for  the  better  will  be  made, 
but  it  will  cease  soon  after  these  alterations  cease.  If,  however, 
the  alteration  is  permanent,  then  the  value  of  M  will,  of  course, 
be  permanently  affected  by  it. 

We  have  often  assumed  certain  conjectural  values  for  some 
of  the  factors;  does  this  fact  invalidate  the  reasoning?  We 
will  examine  these  values  more  closely  in  the  next  section, 
but  the  exact  figures  do  not  affect  the  general  law.  We  have 
supposed  that,  in  equation  (7),  r\b'^si=\o\  from  which  we 
argued  that  the  ultimate  malaria  ratio  will  vanish  if  the  number 
of  different  Anophelines  to  each  person  is  less  than  about 
40  per  month.  The  actual  number  may  be  more  or  less,  but 
the  fact  that  a  limit  must  be  reached  remains.  As  I  have  said, 
the  whole  calculation  is  useful,  not  so  much  for  its  numerical 
results,  but  because  it  gives  precision  to  our  ideas. 

A  more  serious  objection  is  that,  in  framing  the  funda- 
mental equation  (4),  we  have  disregarded  certain  factors  which 
would  modify  it.     For  example,  the  population  will  be  subject 


i64  MALARIA   IN   THE   COMMUNITY  [Sect. 

to  constant  changes  owing  to  immigration,  emigration,  births 
and  deaths — all  of  which  operate  both  on  the  healthy  and 
on  the  infected.  Thus  the  birth-rate  will  give  a  continuous 
supply  of  healthy  individuals,  while  the  death-rate  will  remove 
many  of  the  infected  ones.  Also  many  of  the  recovered  cases, 
and  many  of  the  mosquitos,  may  be  at  least  partially  immune  ; 
gametids  may  appear  in  the  blood  more  during  some  seasons 
than  during  others,  and  infected  mosquitos  may  bite  many 
more  than  one  person  each  ;  but  the  introduction  of  all  these 
factors  would  give  a  much  more  complicated  equation  than 
we  have  need  for  here.     It  will  still  be  of  the  form 

m-J>  =  oi'iginal  cases  +  new  infections  —  recoveries  {or  deaths), 
and    from   this  we   shall    still    be   able   to    argue   that  a  limit 
must   be   reached   when   the   new   infections    exactly    balance 
the  recoveries.     We  may  therefore  conclude, 

(i)  That  the  amount  of  malaria  in  a  locality  tends  towards 
a  fixed  limit  determined  by  the  number  of  malaria- 
bearing  mosquitos  and  by  other  factors. 
(2)  That   if  the  number  of  malaria-bearing  Anophelines 
is  below  a  certain  figure,  that  limit  will  be  zero. 
It    is   often   thought   and    said    that   malaria   should   exist 
wherever  susceptible  Anophelines  exist,  and  that  anti-mosquito 
measures  will  therefore  be  useless    so   long   as   any  of  these 
insects    remain.      But    more    careful    reasoning   will    convince 
us   that   malaria   cannot    persist   in   a   community   unless   the 
Anophelines     are    so    numerous    that    the    number    of    new 
infections  compensates  for  the  number  of  recoveries.^ 

29.  Laws  which  Regfulate  the  Number  of  Anophelines  in 
a  Locality. — We  have  seen,  then,  that  the  amount  of  malaria 
in  a  locality  depends  (among  other  factors)  upon  the  number 
of  suitable  Anophelines,  and  upon  the  proportion  of  them 
which  succeed  in  biting  human  beings,  in  living  long  enough 
to  mature  the  parasites,  and   in  biting   human   beings   again. 

^  See  section  65  (10). 


29]  OUTPUT   OF   MOSQUITOS  165 

We  must  now  study  these  points  in  greater  detail.  Unfor- 
tunately, although  much  entomological  work  has  recently  been 
done  on  mosquitos,  such  important  subjects  as  these  have 
received  little  attention. 

(i).  The  otitpiit  of  mosquitos  from  marshes. — I  know  of  no 
adequate  studies  on  this  point.  In  1908,  in  Mauritius,  I 
stretched  a  mosquito-net  over  9  square  yards  (7"5249  square 
metres),  and  counted  every  day  the  mosquitos  hatched  within 
it.  The  selected  spot  (Clairfond  Marsh)  was  covered  with 
rank  grass,  the  roots  of  which  were  submerged  by  an  inch  or 
two  (2"5-5  cm.)  of  water.  It  was  sheltered  by  trees,  and  was 
an  ideal  spot  for  the  breeding  of  Myzorhynchus  mauritianus 
Daruty  and  D'Emmerez,  1900  (an  Anopheline  which  does 
not  carry  malaria).  The  observations  were  continued  for 
sixteen  days  in  January  (the  warm  rainy  season),  and  only 
this  kind  of  mosquito  was  found.  Altogether  thirty  males 
and  thirty-one  females  were  obtained,^  giving  an  average  of 
0*423  per  square  yard  per  diem,  or  5,062  per  10,000  square 
metres.  Numbers  continued  to  hatch  out  on  the  sixteenth 
day.  During  the  daytime  the  adults  took  refuge  in  the 
grass,  from  which  it  was  necessary  to  expel  them.  Clairfond 
Marsh  is  about  1,400  feet  (427  metres)  above  sea  -  level 
(section  30  (21)  ). 

This  output  (about  5,000  mosquitos  per  diem  for  100  yards 
square  of  marsh)  seems  to  have  been  rather  large,  as  when 
the  net  was  placed  in  another  position  the  yield  was  much 
smaller.  Taking  twenty  days  as  the  average  life  of  an 
Anopheline  (conjecture),  100,000  of  them  should  thus  be  in 
existence  on  any  one  day  in  the  neighbourhood  of  such  a 
marsh  of  about  100  yards  or  metres  square. 

Of  course  the  output  is  sure  to  vary  from  point  to 
point  of  a  marsh,  according  to  the  breeding  capacity  of 
different   depths    of  water,   etc. ;   and    it   will   also   vary   from 

^  Nuttall    and   Shipley   found    equal   numbers   of  males  and   females   with   A. 
maculipennis  also  [January  1902]. 


i66  MALARIA   IN   THE   COMMUNITY  [Sect. 

day    to    day    according    to    the    amount    of    rain,    wind    and 
sunshine. 

Correct  and  sufficient  observations  on  these  points  are 
much  needed.  They  could  be  made  by  the  use  of  small 
square  tents  of  muslin  netting,  supported  by  a  central  pole, 
and  pegged  out  with  weighted  margins  over  a  unit  of  area 
(say  1  square  yard).  We  might  thus  ascertain  not  only  the 
mosquito  output  but  the  length  of  the  aquatic  life  of  mosquitos 
under  natural  conditions,  and  other  facts.  Of  course  a  number 
of  such  tents  must  be  used  to  avoid  much  error  of  random 
sampling. 

(2).  The  average  life  of  the  winged  insects. —  It  used  to  be 
thought  that  mosquitos  feed  on  one  occasion,  lay  their  eggs 
a  few  days  later,  and  then  die.  But  in  1898,  observing  that 
this  short  period  did  not  suffice  to  allow  the  malaria  parasites 
to  develop  fully  in  Culex  fatigans,  I  ascertained  that  these 
insects  could  be  kept  alive  in  captivity  for  a  month,  and 
possibly  much  more,  by  repeated  feedings  [21st  May  1898]  ; 
and  I  obtained  the  same  results  with  certain  Stegomyiae  and 
AnopJielines.  Since  then,  similar  observations  have  been  made 
on  many  mosquitos.  Thus  Goeldi  [1905]  kept  .  a  female 
Stegomyia  calopus  alive  for  102  days,  and  a  male  one  for 
72  days.  The  average  life  in  captivity  of  15  females  was 
53  days,  and  of  1 1  males  was  50  days.  My  general  experi- 
ence has  been  that  it  is  easy  to  keep  various  species  of 
Anophelines  alive  in  captivity  for  two  or  three  weeks,  but 
not  so  easy  to  keep  them  longer.  Nuttall  and  Shipley  [1902] 
kept  A.  niaculipennis  for  56  days,  and  found  that  the  females 
tend  to  live  longer  as  winter  approaches,  possibly  in  connec- 
tion with  hibernation  (Woldert).  It  has  long  been  known 
that  many  mosquitos  hibernate  and  aestivate.  Females  appear 
to  live  in  captivity  longer  than  males.  Better  experiments 
with  large  mosquito-houses,  fixed  in  the  open  air  under  natural 
conditions,  should  be  made. 

But  such  observations  do  not  settle  the  important  question. 


NET    FOR    MEASURING   THE    OUTPUT   OF    MOSQUITOS    FROM    A    MARSH— CLAIRFOND, 

MAURITIUS. 


BANKS    OF   A    STREAM    ROUGH-TRAINED    FOR    RS.O-37    A    RUNNING    FOOT    FOR    BOTH 

BANKS  (MAURITIUS).  {^To  face  page  i66. 


29]  AVERAGE   LIFE   OF    MOSQUITOS  167 

what  is  the  average  \\{g  of  mosquitos  in  nature?     In  captivity 
they  doubtless  suffer  from  confinement,  but,  on  the  other  hand, 
are  preserved  from  their  natural  enemies  and  from  heat,  wind 
and    weather,   which    probably  destroy    immense    numbers   of 
them.     We  should  like  to  know  what  percentages  survive  for 
one,  two,  three    .    .   .   weeks.     Numerous  experiments  on  the 
point  could  be  performed,  but  have  been   neglected.     In  the 
meantime,    I    have   always    taught    the    following   hypothesis. 
The  average  natural  life  of  an  animal  is  likely  to  exceed  that 
of  any  parasitic  organisms  which  it  may  contain.     The  latter 
have  been  instructed,  so  to  speak,  by  the  evolution  of  centuries, 
as  to  the  length  of  time  they  should  spend  over  their  development, 
so  as  to  have  the  best  chance  of  being  propagated  to  other  hosts. 
Thus  Filaria  bancrofti  requires  about  three  weeks  to  develop 
in  Culex.     Now,  if  the  average  life  of  Culex  were  less  than  three 
weeks,  the  filariae  would  have  a  much  smaller  chance  of  pro- 
pagation.   Doubtless,  therefore,  the  average  life  of  Culex  exceeds 
three  weeks  or  a  month.     Similarly,  plasmodia  require  about 
ten  days  to  develop  in  Anophelines,  and   I   therefore  suppose 
that  the  average  life  of  these  insects  reaches  about  three  weeks 
or   more.     But   this   reasoning   suggests   only   the  lower  limit 
of  average  life.     Evidently  a  longer  average  life  would  improve 
the  chances  of  propagation    of  the  parasites.     The   mosquito 
death-rate  must,  of  course,  vary  largely  in  consequence  of  many 
factors,  such  as  season,  enemies,  local  conditions  of  shelter,  etc. 
On  the  whole,  I   think  that  we  shall  not  be  far  wrong  if  we 
accept  our  previous  estimate  that  only  about  one-third  of  the 
carrying  Anophelines  live  for  ten  days — long  enough  to  allow 
the  Plasmodia  to  mature  in  them. 

(3).  The  proportion  of  mosquitos  which  succeed  in  biting  human 
beings. — With  most  species  only  the  females,  that  is,  let  us  say, 
half  the  number,  suck  blood  at  all.  When  a  number  of  females 
are  liberated  all  night  within  a  mosquito-net  occupied  by  a 
man  or  by  birds,  only  a  variable  proportion  are  found  next 
morning  to  be  fed.     Numerous  observations  have  been  made, 


i68  MALARIA    IN   THE   COMMUNITY  [SECT. 

by  myself,  among  others,  which  show  that  the  insects  are  not 
very  hungry  for  about  twenty-four  hours  after  hatching  out 
from  the  pupa,  or  immediately  after  laying  their  eggs.  With 
species  which  attack  animals  (birds,  cattle,  dogs,  etc.),  the 
chances  are  that  the  proportion  of  insects  which  succeed  in 
biting  men  varies  with  the  proportion  which  exists  between 
the  number  of  men  and  of  these  animals  in  the  locality.  Men 
must  be  more  difficult  to  reach  than  defenceless  animals  (or 
children).  The  richer  classes  often  use  mosquito  -  nets ;  and 
poor  natives,  especially  Indians,  generally  cover  themselves  from 
head  to  foot  with  a  sheet  during  sleep,  besides  filling  their  huts 
with  smoke  at  night  time,  and  keeping  their  doors  and  windows 
shut  (the  common  habit,  even  in  hot  climates).  Access  to  people 
in  upper  storeys,  with  small  open  windows,  must  often  be 
difficult  to  these  feeble  insects,  especially  while  any  breeze 
is  blowing. 

I  have  suggested  that  possibly  a  quarter  of  the  Anophelines 
may  succeed  in  biting  human  beings  once,  a  third  may  live 
for  ten  days  more,  and  a  quarter  may  succeed  in  biting  again — 
that  is,  that  only  about  1/24  of  the  females  can  ever  have  any 
chance  of  carrying  malaria.  But  this  applies  only  to. the  pro- 
portion of  mosquitos  to  each  person  in  the  place,  and  supposes, 
moreover,  that  the  human  beings  are  evenly  distributed  in  the 
locality,  and  are  fairly  accessible.  In  thinly-inhabited  places 
the  ratio  will  probably  be  much  smaller,  and  in  crowded  ones, 
larger.  I  think  that  many  insects  which  have  failed  in  pro- 
curing a  meal  during  the  night  may  die  of  starvation  (in  my 
experiments  on  birds  a  number  of  dead  mosquitos  were  generally 
found  in  the  nets  every  morning).  Numbers  of  gorged  mosquitos 
are  probably  devoured  by  bats,  birds  and  spiders,  or  are  killed 
by  sufferers.  On  the  whole,  then,  an  average  ratio  of  1/24  is 
perhaps  too  high. 

Many  observers  have  studied  the  proportion  of  naturally-fed 
Anophelines  which  contain  plasmodia.  In  1899  I  found  the 
parasites    in    27   out   of    109  P.   costalis   caught  in  a  military 


29]  MOSQUITO   DENSITY  169 

hospital  in  Freetown,  Sierra  Leone,  in  which  one  quarter  of 
the  men  examined  contained  them  [1900].  Stephens  and 
Christophers  found  them  in  6/70  of  Anophelines  in  the  same 
town  [5th  April  (?)  1900];  in  5-10%  in  Africa  "as  a  rule"; 
and  in  some  villages  up  to  50%  [1903].  Ziemann,  A.  Plehn, 
the  Sergents,  and  many  others  have  found  similar  rates. 
Unfortunately,  such  observations  do  not  help  us  much,  because 
the  mosquitos  caught  in  houses  may  possibly  be  only  or  mostly 
those  which  have  already  obtained  human  food,  and  are  waiting 
for  more. 

In  the  huts  of  poor  natives,  and  in  badly-managed  barracks 
and  hospitals  where  many  unprotected  people  sleep  in  the  same 
room,  a  single  mosquito  may  often  be  able  to  bite  several 
persons  during  the  one  night.  In  such  houses  the  chances  of 
infection  must  be  enormously  increased,  and  the  practice  of 
congregate  sleeping  must  be  one  of  the  principal  causes  of  the 
diffusion  of  malaria. 

(4).  The  number  of  Anophelines  in  unit  of  area. — Nothing 
approaching  accurate  scientific  work  has  been  done  on  this 
subject.  There  are  many  references  in  literature  to  "  few 
mosquitos,"  to  "  many  mosquitos,"  to  "  swarms  of  mosquitos," 
to  "des  centaines  de  milliers  de  millions,"  and  so  on.  Theobald 
[1901,  I.  72]  describes  having  twice  seen  clouds  of  male  and 
female  C.  cantans  in  the  English  Fens,  darkening  the  air,  and 
producing  a  sound  which  could  at  times  be  heard  a  quarter 
of  a  mile  distant.  He  says  that  W.  W.  Smith  records  that 
a  train  in  New  Zealand  "  passed  through  a  wall  of  mosquitos 
three-quarters  of  a  mile  in  length,  twenty  feet  high,  and  eighteen 
inches  thick " ;  and  he  mentions  dense  masses  of  gnats  "  like 
columns  of  smoke."  If  there  were  ten  mosquitos  to  the  cubic 
foot  in  this  "wall,"  there  would  have  been  only  1,188,000  insects 
in  the  whole  collection — not  a  large  number  considering  the 
possible  output  (i).  Such  phenomena  merely  suggest  that 
occasional  "  swarming "  occurs  with  mosquitos  as  with  other 
animals  (including  man). 


I70  MALARIA    IN   THE   COMMUNITY  [SECT. 

Anophelines  hi  houses  have  been  frequently  caught  and 
counted,  especially  by  Stephens  and  Christophers  and  recent 
observers  in  India.  The  numbers  may  vary  from  zero  to  many 
hundreds  in  a  single  room,  especially  in  thatched  huts.  They 
may  also  vary  from  house  to  house,  and  according  to  distance 
from  breeding  waters.  It  is  impossible  to  quote  any  correct 
averages.  I  have  thought,  as  a  general  conjecture,  that  one 
Anopheline  for  each  human  occupant  might  be  adopted  as 
a  kind  of  standard  for  comparison  ;  but,  of  course,  near  marshes 
the  numbers  often  rise  to  50,100,  or  more  in  each  room,  or  even 
to  each  person. 

We  cannot  estimate  the  number  of  any  species  in  unit  of 
area  by  the  number  caught  in  houses  in  that  area,  unless  we 
know  the  proportions  of  that  species  found  inside  and  outside 
houses  respectively,  at  the  hour  of  the  day  when  the  search 
is  made.  As  we  can  never  know  this  proportion  exactly,  the 
number  of  insects  caught  inside  houses  is  no  exact  guide  to 
the  total  number  existing  within  the  area  of  observation. 

Different  species  appear  to  differ  largely  as  to  the  amount 
of  time  they  spend  in  human  habitations.  I  define  do^nestic 
mosquitos  as  those  which  pass  a  large  part  of  their  lives  in 
houses,  such  as  C.  fatigans,  S.  calopus,  M.  rossii ;  though  even 
with  these  species  we  do  not  know  exactly  how  many  hours 
they  spend  indoors  and  out-of-doors  respectively.  I  define 
sub-domestic  mosquitos  as  those  which  enter  houses  only  for  the 
purpose  of  feeding,  and  wild  mosquitos  as  those  which  never 
enter  houses  at  all.^  Some  species,  such  as  M.  mauritianus,  are 
found  in  verandas  of  houses,  but  not  commonly  in  rooms. 

The  average  output,  average  length  of  life,  and  average 
number  per  unit  of  area  of  any  species  of  mosquitos  are 
correlated  quantities  which  can  be  ascertained  only  by  the 
most  careful  measurements,  such  as  have  never  yet  been 
attempted  (so  far  as  I  can  ascertain). 

1  Arribalzaga  and  Ficalbi  give  similar  classifications.  The  latter's  is  based  on  the 
habits  of  the  larvae. 


29]  MOSQUITO    DENSITY  171 

In  the  previous  section  I  computed  roughly  that  malaria 
is  not  likely  to  persist  in  a  locality  where  the  pathophoric 
Anophelines  number  less  than  about  forty  different  individuals 
to  each  person  during  a  month.  It  would  be  very  difficult  to 
ascertain  anywhere  how  many  different  mosquitos  there  are  to 
each  person,  but  the  attempt  should  be  made.  Mere  personal 
impressions  on  the  point  are  apt  to  be  very  wrong.  The 
victim,  surrounded  by  many  assailants,  tends  to  magnify  their 
number  from  one  to  ten,  and  from  ten  to  a  hundred.  The 
use  of  a  white  muslin  hand  net,  with  which  his  enemies  can 
easily  be  caught,  will  disclose  the  truth.  I  am  inclined  to 
adopt  the  following  standard.  The  mosquitos  in  a  room 
or  veranda  are  nu^nerous  if  a  single  person  is  attacked  by 
more  than  five  at  a  time,  and  very  numerous  if  he  is  attacked 
by  more  than  ten.  There  are  few  houses  in  the  tropics 
where  one  is  not  solicited  day  and  night  by  two  or  three 
mosquitos. 

If  we  count  the  number  of  Anophelines  found  in  a  set  of 
houses  every  day  for  a  number  of  days,  we  could  obtain  the 
average  number  to  be  found  indoors  for  each  person  living  in 
the  locality.  But  we  cannot  say  that  all  these  are  different 
mosquitos.  We  may,  however,  attempt  a  very  rough  com- 
putation as  follows : — Suppose  that  on  the  average  there  are 
10  Anophelines  to  each  person  every  day.  Then,  if  all  the 
insects  are  changed  every  day — that  is,  if  each  insect  lives  only 
24  hours  on  the  average — there  should  be  about  10x30  =  300 
different  insects  to  each  person  during  a  month  of  30  days. 
If,  however,  the  insects  live  for  15  days  on  the  average — 
that  is,  are  changed  twice  a  month — there  should  be  about 
10x30/15  =  20  different  insects  to  each  person  during  the 
month.  If  the  insects  live  30  days,  there  should  be  only 
10  different  ones  to  each  person.  Thus  if  n  is  the  average 
number  of  mosquitos  found  per  diem  per  person,  a  is  the 
number  of  different  mosquitos  per  person  during  a  month  of 
30  days,  and  /  is  the  average  life  of  the  mosquitos  in  days, 


172  MALARIA    IN   THE   COMMUNITY  [Sect. 

we  should  then  have  roughly  a  =  jiXTplL  If  ^  =  27  and  /=  20, 
then  a  =  ^o,  the  number  roughly  computed  as  the  malaria- 
maintaining  limit. 

To  sum  up — if  we  think  over  these  points  carefully  (and 
this  has  not  always  been  done),  we  shall  be  convinced  of  the 
great  difficulty  of  forming  any  accurate  notion  of  the  mosquito- 
density  of  any  species  anywhere.  The  enquiry  would  demand 
a  laborious  study  of  the  output,  which  must  vary  from  week 
to  week  ;  of  the  average  life,  which  must  also  vary  ;  and  of  the 
average  numbers  found  in  houses  and  in  mosquito  traps 
(section  12).  It  would  require  the  services  of  a  number  of 
trained  "  moustiquiers,"  and  the  error  would  amount  to  say 
10%  or  more,  even  with  the  most  careful  observations. 

(5).  Variation  of  mosquito-density  from  place  to  place. — It 
would  be  very  interesting  to  determine  the  rate  at  which 
the  mosquito  -  density  falls  at  different  distances  from  a 
single  breeding-place.  Stephens  and  Christophers  [5th  April 
(.?)  1900]  showed  that  in  Freetown,  Sierra  Leone,  the  insects 
were  abundant  in  houses  near  certain  breeding-waters,  but 
diminished  markedly  at  greater  distances.  An  exact  enquiry 
would  be  very  difficult.  We  could  estimate  the  numbers 
caught  in  houses  and  traps  at  various  distances  from  a  single 
pool  in  an  otherwise  sterile  area.  Here  one  source  of  error, 
the  relative  domesticity  of  the  species  investigated,  would 
cancel  out  from  the  ratios ;  and  ceteris  paribus  the  propor- 
tions caught  should  indicate  the  proportions  present.  But 
other  sources  of  error,  facilities  for  obtaining  food  and  shelter 
in  different  houses,  might  disturb  the  results.  An  empty 
farm  close  to  a  marsh  might,  for  instance,  attract  many  fewer 
insects  than  a  small,  crowded  village  half  a  mile  away.  Never- 
theless, we  know  that  as  a  broad  general  rule,  mosquitos  tend 
to  diminish  with  distance  from  their  breeding-place ;  but  the 
exact  curve  of  diminution  has  not  been  ascertained. 

(6).  Variation  of  mosquito-density  from  time  to  time. — Here, 
too,  we  could  count  the  number  of  mosquitos  in  houses  and 


29]  OUTPUT  PER  BREEDING-SURFACE  173 

traps  for  a  series  of  days,  and  the  factor  of  relative  domesticity 
would  be  eliminated  from  the  ratios.  The  total  variation 
obviously  depends  upon  two  factors,  that  of  output  and  that 
of  longevity.  If  both  the  birth-rate  and  the  death-rate  are 
increased  or  diminished,  the  total  density  might  remain  the 
same,  a  fact  which  seems  sometimes  to  have  been  forgotten. 
(7).  Variation  of  mosquito-density  due  to  food,  etc. — Abundance 
of  food  certainly  has  a  great  effect  on  domestic  Culicines, 
which  tend  to  swarm  in  crowded  and  poor  habitations.  Pro- 
bably it  has  a  similar  effect  on  sub-domestic  Anophelines, 
though  these  may  not  be  so  much  in  evidence.  I  mean  that 
abundance  of  food  probably  tends  to  increase  the  output, 
although  the  total  breeding  surface  remains  the  same.  This 
would  be  due  to  the  fact  that  the  females  find  food  more 
easily  and  consequently  lay  more  eggs.  Thus  malaria  may 
perhaps  increase  in  a  locality,  not  because  of  the  increase  of 
breeding-places  or  rainfall,  or  because  of  the  introduction  of 
more  imported  cases,  but  simply  because  an  increase  of  the 
human  population  has  provided  more  food  for  the  Anophelines 
(section  30  (9),  (12),  and  (21)  ). 

(8).  Relation  of  mosquito-output  to  extent  of  breeding-surface. 
— This  is  a  point  of  great  importance  as  regards  prevention.  If 
we  reduce  the  extent  of  breeding-surface  to  a  given  pro- 
portion, what  will  be  the  exact  effect  on  the  number  of 
mosquitos  ? 

{a)  The  number  of  larvae  in  a  collection  of  water  will 
depend  (i)  on  the  number  of  eggs  laid  in  it,  and 
(2)  on  the  suitability  of  the  water  —  temperature, 
shelter,  absence  of  enemies,  food. 
{b')  Probably  that  number  cannot  exceed  a  certain  limit ; 
that  is  to  say,  there  must  be  a  maximum  possible 
output  per  unit  of  breeding-surface  at  any  season. 
if)  Probably  also  the  actual  output  is  often  less  than  the 
maximum  possible  output,  the  deficiency  being 
due  to   absence   of   enough    food    for   the   females, 


174  MALARIA   IN   THE   COMMUNITY  [Sect. 

destruction    of    the    adults,    inaccessibility    of    the 
water,  etc. 

{d)  The  maximum  possible  output  per  unit  of  breeding- 
surface  is  likely  to  vary  with  season,  and  to  be 
much  greater  during  the  warm  season  when  the 
food  of  the  larvae  is  probably  more  abundant,  and 
their  development  quicker. 
From  these  data  we  infer  as  follows  : — 

{e)  Suppose  that  the  breeding-surface  of  a  locality  is  yielding 
the  maximum  output,  and  is  then  suddenly  reduced 
in  extent,  say  to  half  or  a  quarter  the  previous  area. 
Then  a  proportional  fall  must  occur  in  the  total 
output  of  mosquitos  in  the  locality. 

(/")  Next,  suppose  that  the  breeding-surface  was  yielding 
only  a  fraction  of  the  maximum  possible  output 
when  the  extent  of  it  was  reduced.  Then  the  fall 
in  the  total  output  of  mosquitos  may  not  be  so  great. 
The  females,  which  formerly  laid  their  eggs  in  the 
part  of  the  area  which  has  been  drained,  may  now 
resort  to  the  pools  which  are  still  allowed  to  remain, 
and  may  increase  the  output  of  these  by  stocking 
them  with  an  additional  number  of  eggs.  Thus, 
though  the  total  breeding-area  is  reduced,  the  part 
of  it  which  remains  may  have  a  larger  output ;  so 
that  the  total  output  in  the  locality  may  remain 
the  same  as  before. 

{g)  But  this  compensation  has  its  limits.  If  the  reduc- 
tion of  breeding-area  has  been  great,  the  pools  that 
remain  may  often  be  inaccessible  to  the  females, 
or  may  become  overstocked  with  eggs  and  larvae, 
for  which  they  cannot  provide  enough  food.  At 
best,  the  total  output  cannot  exceed  the  maximum 
possible  output  of  the  waters  which  remain. 

{h)  If  the  drainage  operations  have  been  commenced  early 
in  the  season,  before  the  breeding  -  season    is   fully 


29]  OUTPUT   PER   BREEDING-SURFACE  175 

developed,  and  if  they  have  not  been  complete,  then, 
as  the  breeding-season  advances,  the  waters  which 
remain  will  still  continue  to  have  an  increasing 
output ;  so  that  the  total  output  of  mosquitos  in 
the  locality  may  continue  to  increase  in  spite  of 
the  partial  drainage  operations,  I  say  that,  if  any 
breeding  -  waters  at  all  are  left,  the  output  will 
increase  from  month  to  month  as  the  breeding-season 
advances  to  its  maximum  ;  but  this  does  not  mean 
that  the  total  output  after  the  drainage  operations 
is  not  less  than  the  total  output  in  the  previous 
season  before  the  operations.  The  thoughtless 
observer,  seeing  an  increase  of  mosquitos  due  to 
the  seasonal  increase  of  output  in  the  waters  left 
undrained,  may  jump  to  the  conclusion  that  the 
drainage  has  had  no  effect.  But  a  comparison  of 
the  total  output  before  and  after  the  drainage  would 
probably  correct  this  error.  The  two  issues  have 
frequently  been  confounded  —  as,  I  think,  at  Mian 
Mir.  Of  course,  if  any  breeding  -  waters  at  all 
remain,  a  certain  number  of  mosquitos  will  continue 
to  be  poured  out,  especially  at  the  height  of  the 
breeding  -  season  ;  but  it  is  scarcely  likely,  ceteris 
paribus,  that  a  small  breeding-surface  can  have  as 
great  an  output  as  a  large  one,  and  it  certainly 
cannot  have  more. 
We  conclude  then  as  follows : — 
(i).  That  cete7'is  paribus  the  output  must  tend  to  vary  with 

extent  of  breeding-surface. 
(2).  But  that  the  two  curves  will  not  always  exactly  coincide. 
For  example,  if  the  breeding-surface  is  reduced  to  a  half, 
then  the  output  of  mosquitos  will  also  be  probably  reduced 
very  considerably ;  but  it  may  not  be  reduced  exactly  in  the 
same  proportion.  If  the  breeding- waters  are  entirely  removed, 
then,  of  course,  the  output  in  the  locality  must  entirely  cease. 


176  MALARIA   IN   THE   COMMUNITY  [Sect. 

(9).  Flock-migrations  of  viosquitos. — We  have  hitherto  con- 
sidered the  mosquito  population  of  locaHties  as  if  it  consisted 
solely  of  insects  born  in  the  locality.  But,  obviously,  many 
of  the  insects  found  in  any  area  must  have  entered  from  without ; 
and  we  must  now  examine  the  subject  of  mosquito-migration. 

By  flock-migration  I  mean  the  simultaneous  movement  of 
large  numbers  of  animals  of  the  same  species  in  the  same 
direction  —  such  as  we  are  familiar  with  in  the  case  of  wild 
cattle,  swallows,  locusts,  etc.  Does  anything  of  the  kind  occur 
with  mosquitos?  Howard  [1901]  quotes  a  letter  in  which  flock- 
migrations  of  immense  numbers  of  mosquitos  are  reported  to 
have  been  twice  witnessed  by  the  same  observer  in  America, 
It  was  supposed  that  the  insects  had  originated  in  a  large 
marsh  35  miles  distant ;  and  they  were  numerous  enough  to 
cloud  the  sky,  and  bend  down  the  grass  with  their  weight, 
Nuttall  and  Shipley  conjecture  [January  1902]  that  the 
phenomenon  may  be  due  to  "  overstocking  of  a  given  locality 
by  a  species."  If  it  has  occurred  once,  it  ought  to  occur 
frequently  enough  to  be  recorded  more  often.  There  is  always 
the  danger  that  a  large  local  hatch-out  may  be  responsible  for 
the  occurrence. 

(10).  Visitation  of  ships. — Mosquitos  frequently  visit  ships 
half  a  mile  or  more  from  the  shore.  We  must  not  infer  that 
they  have  purposely  travelled  so  far  in  search  of  food.  Winged 
animals  which  have  once  started  on  a  flight  across  water  seldom 
have  the  sense  to  return.  At  Highcliffe,  England,  I  once 
watched  numbers  of  butterflies  {P.  brassiccB)  flying  out  to  sea 
from  the  shore  on  a  still  morning — none  were  coming  back. 
Birds  and  insects,  lost  in  this  manner  and  wearied  with  flight, 
naturally  board  passing  ships  for  rest.  Sometimes,  however, 
a  ship  anchored  close  to  shore  may  be  attacked  by  mosquitos 
which  have  perhaps  scented  their  prey  from  a  distance.  On 
the  other  hand,  I  have  often  been  on  board  such  ships  without 
noticing  many  mosquitos.  Once  I  spent  a  night  in  a  small 
open  boat,  rowed  down  a  river  in  Burma,  but  observed  at  the 


29]  TRANSPORTATION   OF   MOSQUITOS  177 

time  that  not  a  single  mosquito  attacked  us,  though  the  night 
was  still  and  warm. 

(li).  Transportation  by  ships  and  vehicles. — I  have  known 
Ctilex  and  Stegoniyia  to  breed  in  water-jugs  and  flower  vases  on 
board  ship,  and  they  frequently  breed  in  bilge-water  and  wooden 
water  barrels.  But  as  soon  as  the  ship  starts  on  her  voyage 
most  of  the  insects  seem  to  be  blown  out  of  the  cabins.  Nuttall 
[1899]  says  that  Roe  once  observed  a  dozen  foreign  species  of 
mosquitos  on  board  a  ship  lying  at  quarantine  in  New  York. 
This  was  probably  a  sailing  ship,  as  the  vibration  of  steamers 
seems  to  prevent  the  insects  coming  to  rest.  Balfour  notices 
that  Anophelines  are  brought  into  Khartoum  in  boats. 

Every  one  who  has  lived  in  the  tropics  has  observed  that 
mosquitos  occur  in  carriages  and  railway  trains.  During  the 
heat  of  the  day  the  insects  seem  unwilling  to  leave  the  vehicle, 
though  it  is  in  motion,  and  may  thus  be  transported  consider- 
able distances.  But  vehicles  which  introduce  mosquitos  may 
also  remove  them,  and  it  is  absurd  to  suppose  that  the  small 
numbers  carried  in  this  way  can  often  influence  the  malaria  rate. 

(12).  Transportation  by  rivers  and  winds. — Nuttall,  Cobbett 
and  Strangeways-Pigg  [1901]  suggested  that  rivers  may  trans- 
port eggs,  larvae  and  pupae,  but  I  think  that  most  of  the 
latter  would  be  devoured  before  they  have  travelled  very  far. 

Many  people  imagine  that  mosquitos  are  carried  by  winds. 
Householders  who  breed  them  in  their  own  premises  like  to 
ascribe  their  presence  to  marshes  some  miles  away.  The 
authors  just  quoted  state  [1901,  p.  8]  that  Fernald  described 
how  mosquitos  at  Cold  Spring  Harbour,  Long  Island,  New 
York,  were  blown  there  from  a  distance  of  15  miles  by  the 
south  wind  ;  but  Nuttall  and  Shipley  [1902,  p.  61]  quote  Weeks 
as  correcting  this  by  showing  the  existence  of  many  breeding- 
places  at  Cold  Spring  Harbour  itself.  When  I  arrived  at 
Freetown,  Sierra  Leone,  in  1899,  every  one  thought  that  the 
local  mosquitos  came  from  marshes  a  mile  or  more  distant : 
they  were  really  being  bred  in  every  house  in  the  town.     I 

M 


178  MALARIA   IN   THE   COMMUNITY  [Sect. 

could  mention  many  more  experiences  of  the  same  kind. 
Statements  regarding  wind  -  transportation  must  be  received 
with  great  reserve,  because  here,  also,  a  local  hatch-out  may  be 
responsible  for  the  facts  stated. 

In  Mauritius  in  1908  I  placed  pickets  of  trained  "  mousti- 
quiers "  at  different  distances  from  Clairfond  Marsh  with 
instructions  to  catch  all  the  Anophelines  which  attacked  them. 
The  men  sat  out  late  at  night  and  brought  us  their  captures  in 
the  morning.  Their  conclusions  were  that  the  insects  scarcely 
move  about  at  all  when  there  is  much  wind.  On  still,  warm 
nights,  however,  especially  after  rain,  the  pickets  caught  both 
P.  costalis  and  M.  mauritianus  half  a  mile  from  the  marsh. 
These  facts  are  opposed  to  those  who  believe  in  frequent  wind- 
transportation,  but  accord  with  the  views  of  Howard  and  others, 
and  myself, 

Occasionally,  of  course,  a  few  insects  may  be  swept  away  by 
wind,  but  in  most  cases  wind  merely  drives  them  into  shelter. 
In  fact,  whenever  there  was  any  wind  our  "moustiquiers"  caught 
adults  only  in  sheltered  spots  behind  houses,  hedges  or  woods. 
I  fancy  that  gnats,  like  other  animals,  dislike  being  swept 
away  from  their  own  haunts  into  unknown  regions., 

I  have  always  used  the  following  good  argument  against  the 
notion  that  wind  transports  mosquitos  to  any  great  extent. 
If  this  were  so,  sea-shores  constantly  swept  by  sea-breezes 
ought  to  be  nearly  free  of  them ;  but  I  can  certainly  bear 
witness  to  the  fact  that  this  was  not  the  case  in  Madras  and 
Port  Said,  when  I  was  in  those  towns  in  1881-1884  and  1902. 
A  strong  sea-breeze  blowing  through  a  house  with  all  the 
windows  and  doors  open  will  not,  in  my  experience,  drive  out 
the  Culicines,  nor  even  reduce  their  numbers. 

(13).  Velocity  and  length  of  flights. — I  am  not  aware  of  any 
experiments  on  these  points,  but  I  have  frequently  observed 
Stegomyiae  flying  against  breezes  which  I  judged  to  be  blowing 
at  over  five  miles  an  hour.  They  can  easily  follow  a  man 
walking,  and  perhaps  a   trotting  horse,     I   suppose  that  they 


29]  FLIGHT   OF    MOSQUITOS  179 

fly  at  the  rate  of  about  eight  miles  an  hour,  roughly 
computed. 

At  this  rate  an  insect  might  easily  cover  ten  or  twenty  miles 
a  day,  and  if  it  were  akvays  to  fly  in  the  same  direction  from  its 
breeding-place^  might  traverse  a  hundred  miles  or  more  during 
its  life. 

Many  absurd  statements,  such  that  mosquitos  can  fly  only 
half  a  mile  or  so  from  their  breeding-place,  continue  to  be 
made.  It  is  not  a  question  of  what  is  their  power  of  flight,  or 
how  far  they  can  fly,  but  of  how  far  they  actually  do  fly  on  the 
average. 

My  proposals  to  reduce  malaria  by  dealing  with  the  breed- 
ing waters  were  long  ridiculed  because  it  was  thought  that  as 
soon  as  the  local  output  was  checked  mosquitos  would  rush 
in  from  outside  to  fill  up  the  deficiency.  Several  eminent 
biologists  held  this  opinion,  and  a  ridiculous  experiment  was 
undertaken,  apparently  in  the  hope  of  proving  it.  In  1903-1904, 
however,  I  attempted  a  carefully  reasoned  consideration  of  the 
whole  subject — so  vital  to  the  interests  of  malaria  prevention  ; 
and  showed  in  a  lecture  [May  1905]  that  the  average  wanderings 
of  the  insects,  and  indeed  of  all  animals,  must  be  limited  by 
laws  of  chance.  I  will  now  explain  that  reasoning  as  simply  as 
possible. 

(14).  Tlie  random  scatter  of  animals  from  a  given  point. — 
Suppose  that  an  animal  is  liberated  at  a  given  point — for 
instance,  a  mosquito  from  a  box — and  suppose  that  it  can  find 
its  food  equally  well  anywhere  in  the  surrounding  country,  and 
is  not  drawn  towards  any  particular  spot,  or  driven  anywhere 
by  wind  or  other  things  ;  what  are  its  movements  likely  to  be.? 
We  can  imagine  that  it  may  just  possibly  continue  always  to 
move  in  the  same  direction,  so  that  when  it  dies  it  will  be  found 
at  the  greatest  possible  distance  from  the  point  where  it  was 
liberated.  Or  it  may  move  for  half  its  life  in  one  direction,  and 
for  the  other  half  of  its  life  back  again — so  that  it  will  die 
actually  at  the  point  where  it  started.     But  both  these  courses 


i8o  MALARIA   IN   THE   COMMUNITY  [Sect. 

will  scarcely  ever  be  adopted.  In  the  vast  majority  of  cases, 
the  animal  will  move  for  a  short  distance,  first  in  one  direction, 
then  at  an  angle  in  another  direction,  then  again  at  another 
angle,  and  so  on  until  it  dies.  Its  movements  will  resemble 
those  of  a  grain  of  dust  placed  on  a  level  plate  in  a  jolting 
railway  carriage ;  or  the  random  walk  of  an  intoxicated  person 
in  a  mist ;  or  that  of  a  cow  grazing  on  a  uniformly  succulent 
meadow.  What  are  the  chances  that  when  the  animal  dies  or 
ceases  to  move  it  will  be  found  at  a  given  distance  from  the 
starting-point  ? 

Obviously,  it  will  most  probably  be  found  somewhere  near 
the  starting-point.  There  is  no  reason  why  it  should  move 
more  in  one  direction  than  in  another.  The  chances  are  equal 
that,  at  any  change  which  it  makes  in  the  direction  of  move- 
ment, it  will  next  move  north,  south,  east  or  west.  Hence  its 
various  movements  will  always  tend  in  the  long  run  to  annul 
each  other — so  that  it  will  tend  to  finish  near  where  it  began. 
But  there  is  no  certainty  that  its  various  movements  will  annul 
each  other  exactly ;  hence,  most  probably,  it  will  not  be 
found  exactly  at  the  starting-point,  but  only  somewhere 
near  it. 

Or  we  may  put  the  problem  thus.  Suppose  that  a  million 
Anophelines  are  liberated  from  a  single  breeding-pool  in  the 
midst  of  a  country  where  they  can  obtain  food  equally  well  at 
any  point,  and  suppose  that  we  know  their  average  rate  of 
movement  and  length  of  life :  how  many  of  them  will  be  found 
at  a  given  moment  at  a  given  distance  from  the  pool  ?  Most 
of  them  will  be  found,  not  exactly  at  the  breeding-pool,  but 
close  to  it.  A  few  will  be  found  further  away,  and  a  very  few 
at  the  extreme  limit  of  possible  flight. 

What  precisely  will  be  the  ratio  of  insects  at  a  given  distance 
from  the  pool  ?  In  my  lecture  just  mentioned  I  attempted  a 
partial  mathematical  treatment  of  the  problem,  but  the  matter 
was  beyond  my  mathematical  powers,  and  I  therefore  referred 
it  to  Professor  Karl  Pearson,  who,  with  J.  Blakeman,  obtained 


29]  RANDOM    SCATTER  i8l 

a    correct    and    complete     solution,     based    on    the    laws    of 
chance  [1906].^ 

It  is  not  possible  to  give  their  complicated  mathematical 
analysis  here,  but  I  will  presently  mention  some  of  their  results. 
Besides  its  application  to  the  prevention  of  mosquito-borne 
disease,  the  mathematical  theory  of  migration  has  manifest  and 
important  applications  in  general  biology,  as,  for  instance,  to  the 
theory  of  evolution  and  the  study  of  local  variation  of  race. 

The  general  results  obtained  from  the  calculations  may  be 
put  as  follows  : — 

{a).  Unless  mosquitos  are  drawn  or  driven  in  any  particular 
direction  or  directions,  their  number  will  tend  to  be 
greatest  somewhere  near  the  breeding-pool,  and  to 
diminish  progressively  at  greater  distances  from  it. 
{b).  Per  co7zlra,  if  the  mosquitos  are  very  numerous,  then, 
ceteris  paribus,  the  breeding-pool  is  likely  to  be  near 
at  hand. 
These  laws  are  confirmed    by  the   general    observation    of 
many  workers  and  of  the  public.     For  example,  Stephens  and 
Christophers  [25th  April    1902]  conclude  that  the  "flight"  of 
M.   culiczfacies,    N.  fuliginoszis    and    N.   stephensi  in    Nagpur, 
India,  is  "  frequently  a  quarter  of  a  mile,  but  does  not  extend 
to  half  a  mile." 

(15).  Exceptions. — These  will  be  due  {a)  to  flock-migration,  if 
it  occurs ;  {b)  to  carriage  by  vehicles,  boats  and  wind  ;  and 
(f),  more  generally,  to  food-pursuit. 

The  law  of  random  scatter  applies  only  if  the  country  affords 
equal  facilities  for  feeding  in  all  directions,  but  if  this  is  not 
the  case,  the  insects  must,  of  course,  go  where  they  can  find 
their  food.  Thus  if  there  is  only  one  breeding-place  and  one 
feeding-place  somewhat  far  apart,  the  females  must  always 
traverse  that  distance  between  feeding  and  laying  their  eggs ; 
and  if  the  distance  is  great,  probably  few  of  the  females  will 
succeed.  If  there  is  only  one  feeding-place  in  the  midst  of 
many  breeding-places,  such  as  a  village  surrounded  by  marshes, 
^  This  paper  is  not  mentioned  in  the  medical  text-books. 


i82  MALARIA   IN   THE   COMMUNITY  [Sect. 

then  quite  possibly  all  the  females  which  can  reach  the  feeding- 
place  will  focus  themselves  upon  it. 

Here  a  law  which  has  not  been  investigated,  though  it  is 
most  important  as  regards  prevention,  comes  into  play.  What 
is  the  maximum  distance  at  which  a  female  mosquito  can  scent 
her  human  prey?  If  this  is  one  mile,  then,  in  the  case  of  the 
single  village,  drainage  for  the  purpose  of  freeing  it  from 
mosquitos  would  have  to  be  carried  out  for  a  radius  of  one  mile 
round  ;  if  only  half  a  mile,  then  for  a  radius  of  half  a  mile  ;  and 
so  on. 

(i6).  Diviinutioji  of  mosquitos  round  a  cejitral  sterile  patch. — 
Suppose  the  case  of  a  plain  with  numerous  breeding-places 
scattered  uniformly  over  it,  and  suppose  that  there  is  a  central 
sterile  patch  in  it — that  is,  a  patch  where,  owing  to  natural  or 
artificial  causes,  the  insects  cannot  breed  :  how  will  this  patch 
affect  the  mosquito  density  round  it  ? 

The  answer  is  obviously  that  the  mosquitos  round  the  patch 
will  be  diminished  by  exactly  the  same  numbers  as  the  patch 
would  have  produced  if  it  had  been  allowed  to  continue  yielding 
an  output  of  mosquitos.  That  is,  by  the  law  of  random  scatter, 
the  diminution  will  be  greatest  over  the  patch,  progressively 
less  as  we  recede  from  it,  and  none  at  all  at  a  sufficiently  long 
distance  from  it. 

If  the  patch  is  very  small,  the  diminution  will  be  very 
small,  even  at  its  centre,  and  will  be  hardly  appreciable  at  a 
short  distance  from  it.  Here,  of  course,  numbers  of  mosquitos 
will  be  able  to  fly  across  the  patch. 

If,  however,  the  patch  is  a  large  one,  few  of  the  mosquitos 
migrating  inwards  from  its  margin  will  be  found,  according  to 
the  law  of  random  scatter,  at  its  centre.  Suppose,  for  instance, 
that  by  this  law  only  i/ioo  mosquitos  are  found  i,ooo  metres 
from  the  centre  of  a  breeding-pool ;  then  conversely,  in  a  sterile 
patch  of  1,000  metres'  radius,  only  about  i/ioo  of  the  mosquitos 
breeding  at  the  patch's  margin  will  be  found  at  its  centre. 

The  diminution  in  mosquito-density  due  to  a  sterile  patch 


29] 


EFFECT  OF  STERILE  PATCH 


183 


will  be  felt  not  only  over  the  patch  itself,  but  to  a  considerable 
distance  beyond  it.  That  is,  the  mosquitos  will  be  diminished 
just  so  far  and  by  just  so  many  as  the  patch  would  have  put 
out  by  random  scatter  if  it  had  been  an  isolated  breeding 
patch,  and  the  surrounding  country  had  been  sterile. 

That  is,  the  diminution  of  density  due  to  an  isolated  sterile 
patch  and  the  increase  of  density  due  to  an  isolated  breeding 
patch  must  always  be,  ceteris  paribus,  equal. 

From  this  it  follows,  in  the  case  of  a  very  large  isolated 
sterile  patch,  that  the  mosquito-density  exactly  at  the  margin 
of  the  patch  should  be  exactly  one-half  the  normal  mosquito- 
density.  This  law  was  stated  in  my  paper,  and  has  been 
confirmed  by  Pearson  and  Blakeman. 

I  gave  also  a  diagram  showing  the  fall  of  the  mosquito- 
density  on  either  side  of  the  straight  boundary  of  a  large 
sterile  patch,  and  now  reproduce  the  more  exact  curve  shown 
by  Pearson  and  Blakeman  for  certain  constants  roughly 
estimated  by  me. 

Fig.  2. 


-\^ 

\ 

hrt^  of 

fmijrAfioa 

htt.  of 

Immigration. 

•i 

\ 

1 

\ 

0? 
.1 

\ 

*» 

V 

iQ 

V 

Rfduied   DensiTy. 


i84  MALARIA   IN   THE   COMMUNITY  [Sect. 

To  understand  this,  we  suppose  that  the  mosquitos  (or 
other  animals)  are  breeding  as  usual  on  the  left — that  is,  in 
the  Area  of  Emigration,  and  that  many  of  them  are  wandering 
across  the  boundary  into  the  sterile  area  (Area  of  Immigra- 
tion). The  curve  beginning  on  the  left  shows  the  fall  of  the 
mosquito-density.  Slow  at  first,  it  increases  rapidly  as  we 
approach  the  boundary  from  outside.  Exactly  at  the  boundary 
it  is  exactly  one-half.  Inside  the  boundary  it  continues  to 
fall,  rapidly  at  first,  and  then  more  slowly  as  we  approach 
the  centre  of  the  sterile  area.  At  the  centre,  if  the  patch  is 
sufficiently  large,  it  should  be  nearly  or  practically  zero. 

The  following  diagram  from  my  paper  shows  the  same 
thing  in  plan. 

Fig.  3. 
a 


Effecr    o?    dTa.ind.gc    oP    a.    thCuld-T   iTea.  ,     i.  IwundiTv    0? 


drained  fl.Tea..        MoMuil'o-deniit'y  keftina  to  diotimsK    aX  The    tiTcU,  &• 
iecome%    orte-haJp  aTthe  bounda.W,  b,   3.nd  •&  $mail,  in^vppreciable, 
OT  2eio  af  and  within  fhe  circle,  c 


29]  IMMIGRATION   AND   SIZE   OF   AREA  185 

We  should  also  understand  the  following  simple  proposi- 
tions. If  a  straight  line  is  drawn  across  a  country  in  which 
mosquitos  (or  other  animals)  are  wandering  equally  and  at 
random,  then  as  many  will  wander  from  left  to  right  of  the 
line  as  from  right  to  left.  Moreover,  the  longer  the  line  the 
more  animals  will  wander  across  it,  ceteris  paribus,  in  unit  of 
time.  This  should  hold  also  for  circles.  Thus,  if  we  draw  two 
circles,  one  100  metres  in  radius  and  the  other  of  1,000  metres, 
ten  times  more  animals  should  wander  across  the  circum- 
ference of  the  latter  than  across  that  of  the  former.  Thus 
the  number  of  immigrants  into  the  large  circle  should  be 
ten  times  the  number  into  the  small  one.  But  the  mosquito 
or  animal  density  is  obtained  by  dividing  the  total  number 
of  animals  by  the  size  of  the  area  ;  and  the  area  of  the 
large  circle  is  10 x  10=  100  times  that  of  the  small  one.  Thus, 
though  ten  times  more  mosquitos  actually  wander  into  the 
large  circle,  yet  the  average  mosquito  density  due  to  immigra- 
tion alone  in  the  large  circle  will  be  only  one-tenth  that  in 
the  small  circle.  Now  if  both  these  circles  contain  sterile  areas, 
the  mosquitos  within  them  can  consist  only  of  immigrants. 
Hence  the  total  mosquito  density  in  the  large  sterile  patch 
will  be  only  one-tenth  that  in  the  small  one.  In  other  words, 
the  larger  the  sterile  patch  the  smaller  will  be  the  mosquito  density 
due  to  immigration  into  it  from  outside.  That  is,  the  larger  the 
area  of  drainage  the  more  effective  it  will  be. 

It  has  often  been  thought,  absurdly  enough,  that  the 
mosquitos  in  an  area  may  not  always  be  reduced  by  render- 
ing it  sterile.  This  can  never  happen  ceteris  paribus,  because 
the  number  of  immigrants  can  never  equal  the  number  of 
immigrants  plus  the  number  of  natives.  But  if  the  area  is 
very  small  it  may  breed  so  few  natives  that  the  reduction 
after  it  is  sterilised  will  not  be  noticeable.  But  by  suitably 
increasing  the  radius  of  the  sterile  patch  we  can  reduce  its 
average  immigration  density  to  any  small  figure  we  please. 

Of  course,   the   immigration    density  is   not    uniform,  but. 


i86  MALARIA   IN   THE   COMMUNITY  [Sect. 

as  already  stated,  begins  at  the  boundary,  at  a  fraction  of 
the  normal  density,  and  from  that  fraction  diminishes  rapidly 
towards  the  centre,  where,  if  the  sterile  patch  is  large  enough, 
it  may  become  practically  zero. 

Pearson  and  Blakeman  have  made  some  exact  estimates 
based  on  rough  constants  supplied  by  me.  For  example, 
in  a  circular  sterile  patch  one  mile  (r6  kilometres)  in  diameter 
the  mosquito  density  should  be  reduced  at  the  boundary  to 
about  75%  of  the  normal  density;  to  i8%  a  quarter  of  a  mile 
from  the  boundary  ;  and  to  30%  at  the  centre.  If  the  sterile 
patch  is  two  miles  long  and  one  mile  broad,  the  central 
density  should  be  1%.  In  a  sterile  square  mile,  the  density 
should  be  50%  at  the  boundary,  11%  half-way  to  the  centre, 
and  2%  at  the  centre.  In  section  28  I  attempted  to  calculate 
the  probable  fall  in  the  malaria  rate  which  may  result  from 
a  decrease  in  the  number  of  mosquitos. 

30.  Explanation  of  Various  Phenomena. — In  the  previous 
sections  I  have  endeavoured  to  give  the  general  theorem  of  the 
spread  and  prevalence  of  malaria.  We  have  now  to  apply 
this  theorem  to  the  explanation  of  numerous  phenomena  which 
have  been  observed  in  connection  with  the  epidemiology  of 
the  disease. 

From  section  28  (equations  4  and  7)  we  have  the  two 
following  formulae : — 

Variation  Fonuula,  m^  =  nt  +  U^si'a  ( i  —  in)  m  —  rnt 

—  m  +  0'005  a  (i  —vi)  ;;/  — 0"2  m  (say) 

Static  Formula  M  =  i  —  rjb'sia 

=  I  —  200r/a  (say). 

The  Jlrst  formula  suggests  the  manner  in  which  malaria 
varies  in  a  locality.  Here  in  is  the  proportion  of  infected 
persons  at  the  beginning  of  the  enquiry  ;  a  the  proportion  of 
different  carrying  Anophelines  to  each  person  (healthy  or 
infected)    during  the  enquiry  ;  r  the  rate  of  recovery  ;  d   the 


3o]  CONNECTION   WITH    MARSHES  187 

proportion  of  Anophelines  which  succeed  in  biting  men ;  j' 
the  proportion  of  AnopheHnes  which  succeed  in  maturing  the 
parasites ;  i  the  proportion  of  patients  with  gametids  in  their 
blood ;  and,  finally,  m^  the  proportion  of  infected  persons  at 
the  end  of  the  period  of  enquiry.  Here  7//,  r,  b^  s,  i,  in  are 
all  fractions.  I  suppose  conjecturally  that  if  the  enquiry  lasts 
one  month  b'^si =0'00$  (about),  and  r  =  0'2. 

The  second  formula  suggests  the  final  or  static  level  M^  to 
which  the  proportion  of  infected  persons  falls  so  long  as  the 
proportion  of  Anophelines,  «,  and  the  other  factors  remain 
about  constant. 

The  exact  numerical  values  of  b,  s,  z,  do  not  materially 
affect  the  general  argument.  The  equations  omit  several  minor 
factors,  but  are  still  useful  for  giving  precision  to  our  ideas. 

(i).  Connection  with  marshes. — The  fact  that  malaria  tends 
to  be  very  prevalent  near  marshes  was  observed  by  the  ancients, 
has  given  the  name  paludisni  to  the  disease,  and  is  perhaps 
the  most  fundamentally  important  fact  of  our  subject.  It  is 
easily  explained  because  most  Anophelines  breed  principally 
in  marshy  waters,  and  because,  by  the  law  of  random  scatter 
in  (14)  of  last  section,  they  will  generally  tend  to  be  most 
numerous  near  their  breeding-pools.  By  the  static  formula, 
the  larger  a  becomes,  the  more  M  approximates  to  unity — 
that  is,  almost  the  whole  population  becomes  infected.  Per 
contra,  the  further  we  recede  from  an  isolated  marsh  or  other 
isolated  breeding  area,  the  smaller  the  mosquito  density  becomes, 
and  M  falls  in  value.  When  we  reach  such  a  distance  from 
the  marsh  that  a  becomes  40  (conjecturally)  or  less,  the  static 
malaria  tends  to  disappear  altogether. 

Of  course  there  are  many  factors  which  may  possibly  modify 
the  exact  paludo-peripheral  distribution  of  malaria ;  such  as 
the  existence  of  abruptly-rising  ground,  or  of  open  water,  or 
of  thick  forest  close  to  the  marsh  ;  or  (?)  a  strong  wind  con- 
tinuously prevalent  in  one  direction.  Species  of  Anopheline 
may  affect  the  radius  of  distribution.     Where  there  are  many 


i88  MALARIA   IN   THE   COMMUNITY  [Sect. 

scattered   breeding-places    within    range    of  influence   of  each 
other,  the  malaria  will  tend  to  be  more  equally  distributed. 

The  fundamental  fact  has  been  noticed,  if  not  studied, 
everywhere,  especially  in  Italy.  Stephens  and  Christophers 
[April  1902],  in  a  paper  on  the  factors  which  determine 
endemicity,  conclude  from  a  number  of  scattered  observations 
in  India  that  "other  things  being  equal,  there  is  a  direct 
relation  between  the  extent  and  proximity  of  breeding-grounds, 
the  number  of  Anopheles  in  the  houses,  and  the  endemic 
index."  Unfortunately  they  give  only  ratios,  and  these  only 
for  entire  villages  at  various  distances  from  the  breeding- 
grounds.  In  1908,  C.  E.  P.  Fowler  and  I  made  an  exhaustive 
study  of  spleen  rates  of  children  in  houses  scattered  close 
round  the  Clairfond  Marsh  in  Mauritius  (section  30  (21),  and 
map  opposite).  We  found  an  extremely  rapid  fall  in  the  spleen 
rates  even  at  a  distance  of  200-300  metres  from  the  principal 
pools  of  the  marsh.  In  the  three  rows  of  barracks  of  the 
British  soldiers,  the  nearest  of  which  was  850  yards  {jjy 
metres)  from  the  nearest  pool  of  the  marsh,  and  the  furthest 
about  200  metres  further,  Colonel  Peterkin,  the  Principal 
Medical  Officer,  found  that  the  ratios  of  malaria  cases  to  men 
were  31/206=150/1,000,  22/252  =  88/1,000,  and  2/62  =  32/1,000, 
in  the  successive  rows.  Many  other  instances  might  be  cited 
from  the  literature. 

The  definition  of  the  word  "  marsh "  as  here  employed  is 
a  very  important  point.  Webster,  for  instance,  defines  a 
marsh  as  *'  a  tract  of  soft  wet  land  commonly  covered  partially 
or  wholly  with  water."  This  definition  includes  the  marshy 
borders  of  rivers  and  lakes,  etc.  ;  but  we  must  extend  it,  for 
the  purpose  of  our  present  technical  meaning,  to  exclude 
the  idea  of  permanence.  In  our  sense,  marshes  may  be  quite 
temporary — may  exist  only  for  a  few  weeks  during  the  rainy 
season,  or  season  of  floods,  or  wet  cultivation.  The  reader 
must  not  imagine  that  Anophelines  breed  only  in  permanent 
marshes.     I    have   often    thought   that   water  -  logged    country 


VET  ROAD 

fractions  give  the  spleen  ratios  : 
\To  face  page  iSS. 


PLAN  OF  VACOAS  CAMP 

and 

CLAIRFOND  MARSHES. 


Settle 
lOOO  feiit  to  tfui  incA. 


RAVET  ROAD 


Enlargement  of  spleen  in  children  living  round  Clairfond  Marsh.     The  principal  pools  are  shown  in  black.     The  fra 
thus  9/24  denotes  that  9  out  of  24  children  had  splenic  enlargement. 


tions  give  the  spleen  ratios  : 


3o]  CONNECTION   WITH    SOIL   AND   SLOPE  189 

may  often  be  really  less  favourable  to  them  than  a  usually 
dry  country  which  may  be  covered  during  the  rainy  season 
by  extensive  temporary  marsh.  In  permanent  pools,  the  larvae 
probably  have  many  enemies  —  fish,  beetles,  tadpoles,  other 
larvae — which  cannot  live  so  easily  in  the  shallow,  evanescent 
pools  caused  by  rain  at  certain  seasons.  It  is  quite  possible 
that  for  this  reason  a  unit  of  temporary  marsh  has  an  actually 
larger  annual  Anopheline  output  than  a  unit  of  permanent 
marsh,  and  this  consideration  may  help  to  explain  the  great 
prevalence  of  malaria  in  certain  dry  countries,  as  in  the  north 
of  India. 

(2).  Connection  with  soil. — Obviously,  an  impermeable  soil 
is  likely  to  possess  more  collections  of  surface-water  than  a 
loose,  porous  one,  and  thus  to  increase  a,  the  number  of 
Anophelines.  A  sub-soil  stratum  of  rock  or  clay  has  often 
been  mentioned  as  increasing  malaria. 

It  is  possible,  also,  that  certain  soils  are  favourable  to  the 
breeding  of  the  local  malaria-bearing  mosquitos,  while  others 
have  the  opposite  tendency. 

There  is  much  old  literature  on  this  point — written  when 
malaria  was  attributed  to  the  soil.  After  considering  it,  I  think 
it  is  scarcely  worth  reference,  although  much  of  the  work  was 
carefully  done.  There  is  never  any  proof  that  the  variations 
of  malaria  attributed  to  differences  of  soil  were  not  really  due 
to  other  causes.  I  am  far  from  saying  that  soil  exerts  no 
influence  on  the  endemicity  ;  but  J  can  find  no  decisive  evidence 
that  it  does  so,  apart  from  the  merely  mechanical  effect  of 
permeability.  The  matter  deserves  more  exact  study  by  modern 
methods. 

(3).  Connection  with  slope. — i\brupt  hillsides  have  little  malaria 
as  a  rule,  but  Anophelines  often  breed  in  dry  beds  of  torrents, 
as  (for  instance)  described  by  F.  Smith  and  A.  Pearse  in  Sierra 
Leone  [1904].  I  was  infected  in  1897  in  such  a  place,  Kalhutti, 
near  Ootacamund,  India  [February  1898],  and  the  native  servants 
of  the  house  were  attacked  there  also.    Small  flat  valleys  among 


3o]  CONNECTION   WITH    SOIL   AND   SLOPE  189 

may  often  be  really  less  favourable  to  them  than  a  usually 
dry  country  which  may  be  covered  during  the  rainy  season 
by  extensive  temporary  marsh.  In  permanent  pools,  the  larvae 
probably  have  many  enemies  —  fish,  beetles,  tadpoles,  other 
larvae — which  cannot  live  so  easily  in  the  shallow,  evanescent 
pools  caused  by  rain  at  certain  seasons.  It  is  quite  possible 
that  for  this  reason  a  unit  of  temporary  marsh  has  an  actually 
larger  annual  Anopheline  output  than  a  unit  of  permanent 
marsh,  and  this  consideration  may  help  to  explain  the  great 
prevalence  of  malaria  in  certain  dry  countries,  as  in  the  north 
of  India. 

(2).  Connection  with  soil. — Obviously,  an  impermeable  soil 
is  likely  to  possess  more  collections  of  surface-water  than  a 
loose,  porous  one,  and  thus  to  increase  a,  the  number  of 
Anophelines.  A  sub-soil  stratum  of  rock  or  clay  has  often 
been  mentioned  as  increasing  malaria. 

It  is  possible,  also,  that  certain  soils  are  favourable  to  the 
breeding  of  the  local  malaria-bearing  mosquitos,  while  others 
have  the  opposite  tendency. 

There  is  much  old  literature  on  this  point — written  when 
malaria  was  attributed  to  the  soil.  After  considering  it,  I  think 
it  is  scarcely  worth  reference,  although  much  of  the  work  was 
carefully  done.  There  is  never  any  proof  that  the  variations 
of  malaria  attributed  to  differences  of  soil  were  not  really  due 
to  other  causes.  I  am  far  from  saying  that  soil  exerts  no 
influence  on  the  endemicity  ;  but  J  can  find  no  decisive  evidence 
that  it  does  so,  apart  from  the  merely  mechanical  effect  of 
permeability.  The  matter  deserves  more  exact  study  by  modern 
methods. 

(3).  Connection  with  slope. — Abrupt  hillsides  have  little  malaria 
as  a  rule,  but  Anophelines  often  breed  in  dry  beds  of  torrents, 
as  (for  instance)  described  by  F.  Smith  and  A.  Pearse  in  Sierra 
Leone  [1904].  I  was  infected  in  1897  in  such  a  place,  Kalhutti, 
near  Ootacamund,  India  [February  1898],  and  the  native  servants 
of  the  house  were  attacked  there  also.    Small  flat  valleys  among 


I90  MALARIA    IN   THE   COMMUNITY  [Sect. 

mountains  are  apt  to  be  very  malarious.  Slope  acts  mechanically 
on  the  drainage,  but  the  labour  and  heat  of  climbing  predispose 
to  chills  and  relapses. 

Flat  plains  at  the  foot  of  mountains — called  /erai  in  India — 
are  notoriously  unhealthy.  This  is  due  to  the  fact  that  they 
receive  all  the  surface-drainage  of  the  rain  on  the  mountains, 
the  water  flowing  from  which  immediately  stagnates  on  the 
flat  levels.  After  heavy  rain  a  whole  mountain  seems  to  ooze 
with  moisture  at  its  base,  springs  often  appearing  considerable 
distances  away  on  the  plain. 

Whether  mosquitos  often  find  their  way  far  up  slopes  is 
doubtful.  In  1899  we  observed  scarcely  a  single  Anopheline 
in  the  barracks  at  Tower  Hill,  a  small  open  hill  in  the  centre 
of  Freetown,  Sierra  Leone,  with  numerous  breeding-pools  only 
about  500  metres  distant.  Infections  among  people  living  at 
a  small  height  on  slopes  is  probably  more  often  due  to  the 
visits  they  pay  to  the  plain,  rather  than  the  visits  paid  by  the 
Anophelines  of  the  plain  to  them. 

(4).  Connection  ivith  vegetation.  —  Several  Anophelines  are 
known  to  breed  in  plants  and  trees.  Certainly,  many  Culicines 
do  so,  and  also  seem  to  like  the  shelter  from  sun  and  wind 
given  by  dense  vegetation.  Our  "moustiquiers"  in  Mauritius  had 
no  difficulty  in  securing  Anophelines  in  the  densely  -  wooded 
"  river  reserves."  But  I  do  not  know  any  numerical  researches 
which  have  been  made  to  prove  that  any  malaria-bearing  species 
abounds  more  in  woods  than  on  open  ground  (see,  however, 
sections  57  and  63). 

It  has  been  proved  statistically  by  Mr  Walter  of  the 
Mauritius  Observatory  that  the  damp  exhaled  by  trees  increases 
the  number  of  rainy  days,  and  especially  the  afternoon  rainfall 
so  frequently  seen  in  the  tropics.  For  this  reason  alone,  there- 
fore, trees  should  favour  the  breeding  of  mosquitos. 

It  is  generally  held  that  a  screen  of  trees  shuts  out  malaria 
and  mosquitos  —  this  being  one  of  King's  original  arguments 
in  favour  of  the  mosquito  theory.     Stephens  and  Christophers 


3o]  CONNECTION   WITH    RAINFALL  191 

also  accept  the  hypothesis.     It  is  a  likely  one,  but  better  proof 
is  required. 

The  fact  that  the  true  Plasmodiidae  have  hitherto  been 
found  only  in  men,  monkeys,  bats,  squirrels  and  perching  birds 
is  a  curious  one,  which  suggests  an  arboreal  connection. 

(5).  Connection  with  rainfall  is  manifestly  due,  in  the  case 
of  summer  rain,  to  the  increased  mosquito  output.  Rain  also 
tends  to  bring  on  relapses,  and  therefore  to  increase  the  factor — 
since  patients  with  frequent  relapses  tend  to  show  more  gametids 
than  those  without  them  (section  20  (6)).  Thirdly,  I  think  that 
it  increases  the  biting  factor,  b,  and  quite  possibly  reduces  the 
recovery  factor,  r.  Hence,  on  all  counts  it  must  tend  to  increase 
the  malaria. 

Winter  rain  may  possibly  reduce  r,  but,  if  the  winter  is  cold 
enough,  can  have  little  other  effect.  Thus  in  Greece  most  of 
the  rain  falls  in  the  winter,  when  there  is  little  new  infection. 

Much  spring  rain,  however,  has  a  very  disastrous  and  well- 
known  effect,  as  it  fills  the  pools  just  when  the  weather  is 
becoming  warm  enough  for  breeding.  This  has  been  especially 
noted  in  Greece. 

Statistics  support  the  common  statement  that  malaria 
inoculation  occurs  most  frequently  at  the  beginning  and  the 
end  of  great  summer  rains.  At  the  height  of  these  rains,  when 
they  are  copious,  the  ground  is  often  covered  with  more  or 
less  running  water,  frequently  containing  myriads  of  small 
fish,  and  too  disturbed  for  much  breeding. 

On  the  other  hand,  in  countries  with  small  total  summer 
rainfall,  the  maximum  breeding  is  more  likely  to  occur  at  the 
height  of  it.  There  was  a  bad  outbreak  in  the  north  of  India 
in  1908,  when  most  of  the  rainfall  was  concentrated  in  the 
month  of  August. 

Innumerable  statistics  showing  the  connection  between  rain- 
fall and  malaria  might  be  reproduced  here.  Unfortunately, 
while  they  prove  the  existence  of  the  connection,  they  do  not 
enable  us  to  discriminate  between  inoculations  and  relapses. 


192  MALARIA   IN  THE   COMMUNITY  [Sect. 

Most  probably  the  variation  formula  is  affected  by  changes 
in  all  the  factors  mentioned  above. 

(6).  Connection  with  temperature,  like  that  with  rainfall,  is 
probably  due  to  increase  of  all  the  factors  and  decrease  of  the 
recovery  factor  r  consequent  on  exposure  to  heat  or  sun. 
Warmth  is,  of  course,  an  essential  to  copious  breeding,  but 
great  dry  heat  must  tend  to  desiccate  the  pools. 

An  important  question  remains  to  be  considered.  In  low 
latitudes  the  temperature  is  generally  uniformly  hot  all  the 
year  round,  so  that  the  Anophelines  should  be  able  to  breed 
at  all  seasons,  especially  where  the  rainfall  is  also  fairly  evenly 
distributed.  But  in  higher  latitudes  the  breeding  can  occur 
only  during  the  short  hot  weather.  Hence  we  should  infer  that 
the  Anopheline  factor  must  always  be  higher  in  the  former, 
and  the  malaria  more  abundant.  But  statistics  often  show 
that  just  the  opposite  happens.  For  example,  in  the  north 
of  India,  where  the  winters  are  sharp,  the  total  fever  rate  is 
generally  considerably  higher  than  in  the  south,  where  there 
is  no  winter.  Malaria  is,  or  was,  intense  at  Peshawar  in  the 
extreme  north,  and  scarce  in  Calcutta,  Madras,  Rangoon  and 
Colombo.  But  this  law  does  not  always  hold,  for  malaria  is 
common  in  Panama,  Colon,  Lagos,  Freetown  and  Port  Louis 
(Mauritius),  all  of  which  have  a  climate  very  similar  to  that 
of  the  four  Indian  coast  towns.  (I  write  from  personal 
acquaintance). 

The  probable  explanation  is  as  follows.  So  far  as  we  can 
judge,  not  all  the  Anophelines  can  carry  malaria,  and  various 
carrying  species  differ  in  carrying  power,  thus  modifying  the 
carrying  factor,  s.  It  does  not  follow  that  of  all  the  Anophelines 
of  a  country  those  with  high  carrying  power  breed  best  in  a 
uniformly  warm  climate.  Stephens  and  Christophers  showed 
this  well  in  their  paper  just  referred  to.  Thus  M,  rossii,  with 
a  low  carrying  power,  prevails  most  in  Calcutta  and  Madras. 
See  ( 1 1 )  below. 

(7).  Connection  with  altitude. — It  is  well  known  that  malaria 


3o]  CONNECTION   WITH   ALTITUDE  193 

tends  to  diminish  and  cease  at  an  altitude  of  about  500-1500 
metres  above  sea-level.  The  exact  limit  probably  depends 
upon  the  latitude.  I  was  infected  in  1897  at  1,800  metres  in 
the  Nilgiri  mountains  in  India.  The  disease  abounds  at 
Cilaos,  Reunion,  at  1,214  metres.  The  text-books  quote  many 
similar  cases,  but  these  often  require  verification.  It  is  more 
interesting  to  ascertain  the  gradual  fall  in  the  malaria  curve 
with  altitude.  Stephens  and  Christophers,  misled,  I  think,  by 
insufficient  random  sampling,  thought  that  altitude  under  4,000 
feet  (1,219  metres)  "does  not  seem  to  play  an  important  part," 
but  our  copious  figures  of  spleen  rates  in  Mauritius  (section  22) 
prove  that  it  does.  That  island,  consisting  almost  everywhere 
of  plateaus  sloping  gradually  downward  and  therefore  being 
capable  of  breeding  at  all  the  altitudes  (from  o  to  549  metres), 
gives  an  excellent  opportunity  for  the  enquiry,  as  will  be  seen 
by  study  of  the  table  referred  to.  The  carrying  Anopheline 
was  probably  entirely  M.  costalis. 

As  is  well  known,  the  temperature  of  the  air  tends  to  fall 
about  1°  F.  for  every  300  feet  of  altitude  (about  0"56'  C.  for 
100  metres).  The  general  decrease  of  malaria  with  altitude 
is  probably  due  mostly  to  this  fall  in  temperature,  but  in 
Mauritius,  and  perhaps  in  many  other  places,  other  factors 
besides  temperature  may  retard  the  breeding  of  the  local 
carriers  at  the  higher  levels.  The  following  table,  calculated 
from  that  in  section  22,  gives  the  spleen  rates  and  average 
spleen  for  groups  of  altitudes : — 

altitudes  {feet)  0-300       3-600       6-900       9-1200       12-1500       15-1800 

fall  of  temperature         0°  F.  i  2  3  4  5 

spleen  rates  44*5         41-2         31-5  8-5  10-2  47 

average  spleeft  2-98         3"o8         2-03  r23  r56  r22 

The  exceptional  figures  at   1,200-  1,500  feet  were  due  to   the 

epidemic  round   Clairfond   Marsh.     Apart  from  these,  the  fall, 

both  in  spleen  rates  and  average  spleen,  is  not  noticeable  under 

600  feet,  and  then  becomes  very  rapid  up  to  1,200  feet — after 

which,  under  normal  circumstances  in   Mauritius,  the  malaria 

N 


194  MALARIA   IN   THE   COMMUNITY  [Sect. 

is  slight,  or  possibly  only  imported.  Other  facts  will  be  elicited 
when  governments  get  into  the  way  of  collecting  spleen  rates 
annually,  as  they  should  do. 

(8).  Comparative  freedom  of  centre  of  towns, — It  is  generally 
stated  as  a  commonplace  that  malaria  abounds  less  in  the 
centre  of  towns  and  more  in  the  suburbs  ;  and,  from  my  own 
general  observation^  this  appears  to  be  the  case  in  all  the  larger 
towns  known  to  me.  But  the  matter  requires  strict  enquiry  by 
measurements  of  malaria  made  on  proper  principles  from  the 
centre  outward. 

The  probable  explanation  is  that  the  Anophelines,  though 
they  may  breed  in  small  numbers  in  wells,  cisterns,  gutters, 
waste  from  water-taps,  etc.,  in  towns,  yet  cannot  generally 
propagate  so  copiously  and  freely  there  as  in  the  more  open 
regions  in  the  outskirts.  Probably,  also,  as  the  wealthier  people 
generally  live  in  the  better  built  and  paved  centre  of  a  city,  the 
recovery  factor  is  increased  and  the  gametid  factor  decreased 
there  by  the  good  medical  treatment  usually  accessible  to  these 
classes.     But  there  is  also  the  following  factor. 

(9).  Effect  of  density  of  hwinan  population. — Suppose  that  in 
a  locality  the  mosquito  population  remains  the  same,  but 
that  the  human  population  varies  :  what  will  be  the  effect  of 
this  variation  on  the  malaria  ratio?  By  the  static  formula 
M=i—4.oja;  but  a  is  the  number  of  Anophelines,  not  in  unit 
of  space,  but  per  unit  of  human  population.  If,  therefore,  the 
latter  is  doubled  while  the  total  mosquito  population  remains 
constant,  a  will  be  halved  ;  and  so  on.  Thus  the  static  malaria 
ratio  tends  to  decrease  with  increase  of  the  density  of  the 
human  population.  That  is,  other  things  being  equal  and  the 
Anophelines  being  supposed  to  breed  equally  everywhere,  the 
malaria  ratio  should  be  higher  amongst  a  scattered  rural 
population  than  in  a  dense  urban  one,  because,  evidently,  the 
number  of  Anophelines  per  person  will  be  less  in  the  latter. 

But  I  am  not  sure  that  if  the  human  population  varies,  the 
mosquito  population  will  generally  remain  the  same.     Unless 


3o]  CONNECTION    WITH    POPULATION  195 

the  latter  find  abundance  of  food  independently  of  the  former, 
their  numbers  are  likely  to  diminish  if  the  former  diminishes 
(section  29  (7) ).  This  will  depend  largely  upon  whether  the 
local  carrier  is  a  domestic,  sub-domestic  or  wild  species,  and  on 
other  circumstances. 

If  the  total  mosquito  population  varies  directly  with  the 
human  population,  the  factor  a,  and  therefore  the  static  malaria, 
should  remain  constant  —  that  is,  change  of  density  of  the 
human  population  will  not  affect  the  result. 

If  the  mosquito  population  diminishes  as  the  human  popula- 
tion increases,  the  malaria  ratio  should  fall  greatly — as  in  well- 
drained  towns.  If  the  former  increases  with  the  latter  but 
more  rapidly,  the  malaria  should  increase. 

It  may  happen  that  when  the  human  population  begins  to 
increase  the  local  breeding  surface  is  already  yielding  its 
maximum  output  of  mosquitos.  In  this  case  the  increase  of 
the  human  population  should  cause  a  decrease  in  the  static 
malaria  ratio  (section  29  (8) ). 

In  all  these  cases  the  malaria  ratio  is  not,  of  course,  the  same 
thing  as  the  total  number  of  patients. 

If  the  local  carrier  belongs  to  a  species  or  variety  which 
feeds  almost  entirely  upon  man,  and  if  the  human  population 
is  greatly  reduced,  it  may  perhaps  follow  that  this  species  can 
no  longer  continue  to  thrive  in  the  locality — so  that  the  malaria 
should  die  out.  Dr  Castel  showed  me  a  large  marshy  area  in 
Mauritius  which,  he  said,  was  formerly  thickly  inhabited  ;  but 
the  disease  became  so  prevalent  there  that  the  people  deserted 
it  in  large  numbers.  Now  it  contains  only  a  few  scattered  huts, 
the  occupants  of  which  show  a  low  spleen  rate  (with  P.  costalis). 

(10).  The  "■  regional  factor"  —  It  often  happens  that  two 
neighbouring  tracts  of  country,  apparently  similar  in  all 
respects  such  as  climate,  breeding  surface,  habits  of  people, 
differ  largely  in  the  malaria  ratio.  Stephens  and  Christophers 
[25th  April  1902]  attributed  such  variation  to  "undefined  causes 
which  we  have  termed  the  regional  factor.     The  regional  factor 


196  MALARIA   IN   THE   COMMUNITY  [Sect. 

may  be  largely  due  to  species,  but  more  accurate  and  detailed 
observations  on  the  distribution  of  Anopheles  and  malaria  are 
necessary  before  this  can  be  decided."  It  may  be  due  to  many 
small  things  which,  though  not  very  apparent  to  the  observer, 
may  largely  affect  the  mosquito  factors  b,  .y,  a.  Thus  the  local 
carrier  in  the  larval  stage  may  require  a  certain  kind  of  food 
which  abounds  in  water  lying  on  certain  soils  present  in  one 
locality  and  not  in  others.  Again,  certain  soils  may  favour 
special  enemies  of  the  larvae  of  the  carrier — small  fish,  beetles, 
cannibal  mosquito  larvae,  parasites  ;  while  certain  classes  of 
vegetation  may  favour  enemies  of  the  adults.  All  these  are 
likely  to  be  very  potent  causes  of  variation  in  the  mosquito 
factors,  though  they  may  not  be  easy  to  detect  without  long 
enquiry.  If  we  attribute  the  regional  factor  merely  to  "species" 
of  carrier,  we  have  still  to  "  explain  our  explanation,"  since  we 
must  show  why  a  given  species  abounds  more  in  one  area 
than  in  another. 

Hence  I  define  as  follows.  By  regional  factors  I  mean  all 
those  local  conditions,  apart  from  mere  extent  of  breeding 
surface,  which  influence  any  of  the  mosquito  factors  b,  s,  a\ 
that  is,  local  conditions  which  influence  the  output  per  unit  of 
surface,  the  biting  power,  and  the  maturing  power  of  the 
local  Anophelines. 

(ii).  The  species  factor. — This  influences  b  and  s,  the  biting 
and  maturing  powers  of  the  carriers,  which  probably  differ 
largely  with  the  species  or  even  variety  of  the  carrier.  Where 
these  factors  are  high,  a  lower  number  of  Anophelines  will 
produce  a  given  amount  of  malaria. 

Thus  tropical  Africa  appears  on  the  whole  to  be  more 
malarious  than  India — that  is,  the  chances  of  becoming  infected 
in  unit  of  time  and  season  in  Africa  are  said  to  be  greater  in 
Africa  than  in  India.  This  may  be  because  good  carriers  such 
as  P.  cos  talis  and  M.  funesta  abound  more  in  the  former.  In 
India  the  bad  carrier,  M.  rossii,  seems  often  to  crowd  out  the 
more  pathophoric  species. 


3o]  THE   SOCIAL   FACTOR  197 

The  local  prevalence  of  good  carriers  or  bad  ones  must 
depend  not  only  on  regional  factors  but  on  the  general 
zoological  laws  which  determine  diffusion  of  species.^ 

(12).  The  social  factor. — The  factor  b  depends  not  only  on 
the  appetite,  energy  and  enterprise  of  the  mosquitos,  but  also 
on  the  intelligence,  social  status  and  habits  of  their  victims. 
Stupid,  poor,  lazy  people,  living  in  badly-made  huts,  without 
much  clothing  and  without  mosquito-nets,  are  sure  to  be 
bitten  much  more  easily  than  more  civilised  races.  People 
who  burn  wood  or  cow-dung  in  their  houses  in  the  evening, 
or  who  rub  their  skins  with  oil,  earth  or  sandal-wood,  or  who 
close  their  rooms  at  night,  may  perhaps  be  bitten  less  than 
others.  The  subject  is  too  complex  for  detailed  examination 
here.  The  habits  of  man  and  mosquito  are  probably  often 
correlated.  Thus  where  the  principal  carrier  is  an  out-of-doors 
biter,  people  who  sleep  or  work  at  night  in  the  open  are  likely 
to  suffer.  Alcoholism,  opium,  etc.,  lead  to  neglect  of  precautions. 
Children  are  sure  to  be  easy  victims.  Farm  stock  and  dogs 
may  satisfy  many  insects,  and  punkas  and  fans  drive  away 
others. 

Neglect  of  precautions  against  being  bitten  is  likely,  not 
only  to  increase  the  biting  factor,  but  also,  by  section  29  (7), 
the  total  number  of  mosquitos. 

Famine,  poverty  and  other  diseases  will  reduce  the  recovery 
factor. 

(13).  Possible  el^ect  of  malaria  on  the  Anophelines. — As  earl)' 
as  1898  I  thought  it  possible  that  the  parasites  might  injure 
their  insect  hosts,  as  well  as  their  human  ones.  If  this  happens 
we  can  readily  understand  that  an  epidemic  of  malaria  might 
tend  to  limit  itself  by  killing  large  numbers  of  the  carriers 
as  well  as  men.  Thus,  during  an  epidemic  year,  so  many  of 
the  insects  might  die  that  the  breeding  might  subsequently 
be  reduced  for  some  time.  But  there  are  reasons  against  this 
view.     I  could  never  satisfy  myself  that  C.  fatigans,  even  when 

1  Possibly  also  on  the  insects'  food  (section  48). 


198  MALARIA   IN    THE   COMMUNITY  [Sect. 

extremely  heavily  infected  with  Proteosovia,  died  sooner  than 
when  not  infected  at  all.  Probably  they  do  so,  but  only  to  a 
slight  extent.  Then  again,  only  a  small  percentage  of  infected 
mosquitos  are  heavily  infected,  so  that  the  malaria  infection 
is  not  likely  to  make  a  material  difference  in  their  death-rate. 
Lastly,  even  a  severe  epidemic  among  them  will  quickly  be 
compensated  for  by  their  rapid  proliferation. 

(14).  Seasonal  variation.  —  This  is  a  matter  of  universal 
observation.  As  a  general  rule  in  the  northern  hemisphere  the 
disease  reaches  its  maximum  prevalence  in  the  autumn,  say 
October  or  November.  At  that  point,  a  rapid  decline,  the 
winter  fall,  generally  begins,  and  this  continues  for  several 
months  until  early  spring,  say  February  or  March,  when  the 
winter  minimum  occurs.  The  spring  rise  now  takes  place,  and 
the  disease  tends  to  increase  with  more  or  less  regularity  until 
the  next  autumn  maximum.  Of  course,  the  seasons  are  reversed 
in  the  southern  hemisphere.  Innumerable  illustrative  statistics 
might  be  given ;  but  every  one  is  acquainted  with  the 
phenomenon,  and  the  examples  in  section  20  will  suffice  for 
our  present  purpose  (note  that  in  the  Italian  figures  the 
minimum  is  reached  in  June). 

The  causes  of  seasonal  variation  will  be  apparent  from  a 
study  of  the  variation  formula  given  at  the  beginning  of  this 
section.  Thus  the  winter  fall  is  probably  due  to  diminution  of 
the  factors  h,  .v,  a,  in  consequence  of  the  cooler  temperature  or 
drying-up  of  the  rains,  or  of  both  ;  and  also  possibly  to  increase 
of  the  recovery  factor  owing  to  the  more  bracing  climate.  On 
the  other  hand,  the  spring  rise  is  probably  due  to  just  the 
opposite  changes  in  these  factors,  and  possibly  also  to  the 
emergence  of  Anophelines  which  have  been  hibernating  through 
the  winter. 

In  the  tables  in  section  20  I  have  given  the  ratios  between 
the  average  admissions  for  successive  months.  These  can  be 
compared  with  the  variation  formula,  by  supposing  that  m  is 
the  malaria  ratio  for  any  given  month,  and  m^  the  malaria  ratio 


3o]  SEASONAL   VARIATION  199 

for   the    next    month.     Then,   dividing    the    variation    formula 
throughout  by  ;//,  we  have, 

injjn  =  I  +  b-sra{  \—in)  —  r. 
Thus,  take  the  monthly  averages  and  ratios  of  the  native 
troops,  and  suppose  that  only  the  number  of  men  actually 
infected  were  admitted  (section  31  (5))  into  hospital  every 
month.  Then,  out  of  43,330  men  there  were  on  the  average 
922  infected  men  in  February  and  1,030  in  March.  Thus  m  = 
922/43,330  ;  m^  =  1 ,030/43,330  ;  m^jm  =1-12;  i-m  =  0-98  ;  and 
therefore, 

I  •  1 2  =  I  +  0*98  b"sza  —  r. 
Supposing  that  b,  s,  z,  r  have  the  values  assigned  at  the 
beginning  of  this  section,  we  calculate  from  this  that  a  = 
(o*i2  +  o'2)/o*oo49  =  65.  That  is,  as  a  rough  estimate,  there 
may  have  been  about  65  carrying  Anophelines  per  person 
during  the  month  February  to  March  in  order  to  increase  the 
infected  persons  from  922  to  1,030,  and  the  admissions  from 
461   to  515. 

Similarly,  in  order  to  cause  the  great  rise  in  admissions 
among  the  native  troops  from  averages  of  1,689  in  September 
^°  2,955  i"  October,  we  may  estimate  roughly  that  175 
Anophelines  may  have  been  present.  In  order  to  cause  the 
commencement  of  the  winter  fall  from  2,955  admissions  in 
October  to  1,932  in  November,  we  shall  have  from  the  formula 
a  negative  number  for  a — that  is,  according  to  our  data,  there 
should  be  no  Anophelines  biting  at  the  time.  But  of  course 
our  data  are  only  speculative  ones,  and,  as  already  stated,  the 
factors  b  and  s,  as  well  as  the  Anopheline  factor,  are  likely  to 
vary  with  season.  Moreover,  my  estimate  that  the  recovery 
factor  r  equals  about  0*2  is  probably  too  high  for  the  earlier 
months  of  infection. 

(15).  Anmial  variation. — This  also  is  a  matter  of  general 
observation.  In  every  country  there  are  "  good  years,"  "  bad 
years  "  and  "  years  of  epidemic."  This  variation,  when  it  occurs 
over  large  areas,  is  probably  due  principally  to  the  influence  of 


200  MALARIA   IN   THE   COMMUNITY  [Sect. 

climate,  i.e.,  rainfall,  number  of  rainy  days  and  temperature,  on 
the  Anopheline  factor. 

In  the  statistics  of  section  20,  the  numbers  of  admissions 
differ  not  only  for  the  whole  years,  but  also  for  the  same  month 
in  different  years,  and  for  the  European  troops,  native  troops 
and  prisoners,  respectively,  during  the  same  year. 

It  is  interesting  to  note  that  a  considerable  rise  in  the  total 
annual  admissions  may,  by  our  formulae,  be  produced  by  a 
comparatively  small  rise  in  the  Anopheline  factor.  Thus 
among  the  native  troops  there  were  11,293  admissions  in  1903 
against  19,567  in  1901.  But  by  the  static  formulae  the  former 
number  would  be  given  by  «  =  55  and  the  latter  by  a='jo.  It 
would  be  almost  impossible,  for  the  reasons  given  in  section  29 
(4),  to  detect  this  increase  in  the  number  of  Anophelines  (28%) 
by  ordinary  observation.  Hence  the  unwary  observer  might 
assume  that  the  rise  in  the  number  of  cases  was  independent 
of  the  rise  in  the  number  of  Anophelines.  In  fact  this  is  one 
of  the  principal  stumbling-blocks  of  students.  They  observe 
a  considerable  annual  variation  in  the  number  of  cases  with- 
out, apparently ,  any  great  Anopheline  variation.  But  I  doubt 
whether  an  Anopheline  variation  of  as  much  as  50%  or  even  100% 
would  be  easily  detectable  by  the  very  unsatisfactory  methods 
of  counting  mosquitos  at  present  known  to  us.  If  there  are 
over  40  different  Anophelines  to  each  person  per  month,  we 
should  probably  be  able  to  find  only  two  or  three  daily  in  his 
house — and  possibly  less  if  the  insects  are  "  wild  "  ones.  This 
number  might  be  doubled  or  trebled  without  producing  a 
change  which  would  be  readily  noticed  even  after  careful 
observation,  and  long-continued  random  sampling  would  be 
required  to  establish  the  variation  over  a  tract  of  country.  Yet, 
as  we  have  just  calculated,  a  28%  increase  in  the  Anophelines 
might  cause  a  42%  increase  in  static  malaria — that  is,  an  increase 
of  admissions  from  11,293  to  19,567. 

While,  I  think,  the  annual  variation  is  generally  due  to 
climatic  causes,  it   is    very    possible    that   other    factors    often 


3o]  EFFECT  OF  IMPORTED  CASES  201 

influence  it — such  as  poverty  caused  by  increase  in  the  cost 
of  food  (which  would  diminish  the  recovery  factor),  or  move- 
ments of  the  population  which  might  act  in  various  ways. 

(16).  Effect  of  imported  cases. — In  section  28  I  argued  that, 
whatever  the  original  number  of  cases  may  be,  the  malaria 
in  a  locality  tends  finally  to  settle  down  to  a  fixed  static 
ratio  determined  by  the  various  constants.  Thus  if  we 
take  the  case  of  a  village  of  1,000  people,  half  of  whom  are 
infected  to  begin  with,  with  60  Anophelines  per  person,  the 
rate  would  fall  until,  finally,  about  333  persons  are  always 
infected.  If  we  had  started  in  the  same  village  with  the 
same  number  of  Anophelines,  but  only  one  infected  person, 
then  the  rate  would  rise  until  the  same  number  of  infected 
persons  are  found.  But  the  reader  must  not  infer  that  the 
original  malaria  ratio  is  of  no  consequence — that  it  does  not 
matter  whether  many  cases  are  imported  or  not.  True,  the 
ultimate  static  ratio  should  be  the  same,  but  many  months 
may  elapse  before  this  limit  is  reached.  If  there  have  been 
about  333  cases  in  the  village  for  months  or  years  past,  and 
we  now  add  167  imported  cases,  then  (neglecting  the  small 
change  in  the  total  population)  we  should  have  500,  475,  455, 
438  and  424  cases  in  the  four  following  months;  that  is,  167, 
142,  122,  105  and  91  more  cases  than  there  would  have  been 
in  the  village  if  no  imported  cases  had  been  introduced.  This 
would  probably  be  looked  upon  by  the  villagers  as  a  serious 
epidemic  due  to  some  climatic  cause. 

On  the  other  hand,  suppose  that  there  have  been  40 
Anophelines  per  person  in  the  village.  Then  the  static 
malaria  there  would  be  zero.  But  if  500  of  the  villagers  are 
now  replaced  by  500  infected  persons,  the  40  Anophelines, 
though  insufficient  to  maintain  static  malaria,  would  be  suffi- 
cient to  spread  the  disease  to  some  extent  among  the  villagers  ; 
as  will  be  seen  by  comparing  examples  3  and  6  of  section  28 
— that  is,  the  examples  with  40  and  with  o  Anophelines. 
In  four  months  the   former  will  have  500,  450,  409,  376,  348 


202  MALARIA    IN   THE   COMMUNITY  [SECT. 

cases,  some  of  them  among  the  healthy  villagers  ;  and  the 
latter  will  have  only  500,  400,  320,  256,  205  cases,  all  among 
the  imported  persons.  Thus  in  the  former  there  will  be  50, 
89,  120,  143  cases  among  the  villagers,  who  will,  of  course, 
suffer  from  an  epidemic.  But  in  the  end  the  epidemic  will 
die  out. 

In  this  village  then,  40  Anophelines  per  person  will  suffice 
to  spread  the  disease  to  some  extent  from  the  imported  cases 
to  the  healthy  villagers,  though  the  various  small  epidemics 
which  may  be  caused  in  this  way  will  tend  ultimately  to  die 
out.  But  suppose  that  owing  to  the  blocking  of  some  stream 
the  Anopheline  factor  is  increased  to  60.  The  imported  cases 
will  now  not  only  spread  the  disease  to  the  healthy  villagers, 
but  the  epidemic,  instead  of  dying  out,  will  continue  to  increase 
until  the  static  limit  of  one-third  of  the  population  is  reached. 
The  village,  which  previously  suffered  only  from  sporadic  out- 
breaks due  to  imported  cases,  will  now  become  permanently 
infected.  Yet  this  great  change  will  be  due  merely  to  the 
small  increase  of  Anophelines  from  40  to  60  pei'  person — an 
increase  which  few  observers  would  be  able  to  detect. 

It  is  unnecessary  to  labour  this  matter  further — I  have 
already  laboured  it  perhaps  too  much.  The  point  to  be 
understood  is  that  a  small  Anopheline  variation — too  small 
to  be  easily  observed — may  yet  make  a  great  difference  in 
the  local  endemicity.  Below  a  certain  figure  the  Anophelines 
will  be,  according  to  the  laws  of  chance,  too  few  to  produce 
enough  new  infections  to  keep  pace  with  the  natural  recoveries. 
Above  that  figure  they  will  be  sufficient  for  the  purpose,  and 
the  malaria  ratio  will  rise  to  a  definite  static  limit. 

So  far,  this  theorem  has  been  already  given  in  section  28  ; 
but  we  now  perceive  another  point  of  importance.  Though 
the  Anophelines  are  too  few  to  maintain  a  static  endemicity, 
yet  if  any  at  all  are  present  they  may  suffice  (provided  that 
the  other  factors  b,  s,  i,  r  do  not  possess  prohibitive  values)  to 
cause  small  temporary  spreadings  of  the  disease  from  imported 


3o]  ISOLATED   ABNORMAL   AREAS  203 

cases  among  the  local  population.  Only  in  the  case  where 
there  are  practically  no  Anophelines  will  the  imported  cases 
have  no  effect  at  all.  The  reader  will  easily  grasp  this  law 
by  comparing  the  examples  in  section  28. 

The  reader  should  also  remember  another  point.  Our 
formulae  are  based  upon  the  calculation  of  average  chances. 
Thus,  if  the  average  Anopheline  factor  is  over  forty,  and  a 
single  case  of  malaria  is  imported,  we  argue  that  the  chances 
are  that  the  disease  will  spread  in  the  locality.  We  do  not 
say  that  the  disease  must  or  will  spread  to  a  certainty.  The 
laws  of  luck  come  in  here.  The  distribution  of  Anophelines 
cannot  be  absolutely  uniform  in  any  locality.  The  imported 
case  may  come  to  reside  at  a  spot  where  there  are  few 
Anophelines,  so  that  the  chances  are  that  the  disease  will  not 
spread  at  all.  Or  he  may  reside  where  the  Anophelines  are 
a  little  more  numerous,  so  that  only  a  small  temporary  epidemic 
may  be  caused.  Or,  if  he  happens  to  live  where  there  are 
many  Anophelines,  a  permanent  rise  in  the  malaria  rate  may 
be  produced.  Yet  in  all  these  cases  the  average  Anopheline 
factor  for  the  whole  area  under  consideration  may  be  anything. 
Thus,  again,  the  imported  case  may  have  no  gametids  in  his 
blood ;  or  he  may  arrive  in  winter  and  recover  before  the 
mosquito  season ;  or  he  may  use  mosquito  -  nets.  This  will 
be  a  case  of  good  luck ;  but  by  bad  luck  none  of  these  events 
may  occur,  and  an  epidemic  may  be  started  or  increased. 

We  must  now  consider  some  special  cases  of  importation. 

(17).  Isolated  supervialanous  or  infravialariotis  areas. — 
Suppose  the  case  of  a  country  in  which  the  static  malaria  is 
generally  low,  but  in  which  an  isolated  area  becomes,  from 
any  cause,  more  highly  malarious :  what  will  be  the  effect  of 
that  patch  of  high  endemicity  upon  the  health  of  the  surround- 
ing country  of  low  endemicity  ?  Evidently,  unless  the  inhabi- 
tants of  the  supermalarious  patch  are  strictly  confined  to  it, 
some  of  them  will  tend  to  wander  away  from  it,  especially  if, 
as  often  happens,  they  are   actually   driven   out  of  it   by  its 


204  MALARIA   IN  THE   COMMUNITY  [Sect. 

unhealthiness.  If  there  are  any  Anophelines  at  all  in  the 
surrounding  country,  these  emigrants,  when  infected,  may  cause 
local  spreading,  slight,  severe,  transient  or  permanent,  according 
to  the  local  factor.  In  any  case  they  will  tend  to  increase  the 
surrounding  endemicity.  To  calculate  the  increase  from  the 
variation  formula,  we  must  add,  month  by  month,  the  imported 
cases  to  the  number  of  cases  remaining  over  from  the  previous 
month.  Thus,  though  the  static  malaria  ratio  of  the  surrounding 
country  might  be  naturally  low,  the  continued  importation  of  cases 
from  the  focus  of  high  endemicity  might  raise  it  very  considerably. 

It  may  be  said  that  this  process  cannot  continue  for  ever, 
because  the  focus  would  soon  become  depopulated.  This 
certainly  happens  in  some  very  unhealthy  spots  ;  but  in  others 
the  population  of  the  focus  is  maintained  by  constant  immigra- 
tion, so  that  it  continues  to  be  a  perennial  source  of  danger 
to  the  neighbours.  And  its  influence  may  be  felt  for  consider- 
able distances. 

Now,  consider  the  converse  case — that  in  which  an  isolated 
patch  of  low  endemicity  exists  in  the  midst  of  a  larger  area 
of  high  endemicity.  The  effect  should  be  just  the  opposite. 
There  should  be  obviously  less  malaria  in  the  whole  country 
than  if  the  inframalarious  patch  had  not  existed  at  all ;  and 
the  larger  the  healthy  patch,  the  larger  its  influence  will  be. 

In  other  words,  we  assume  that  inequalities  of  malaria 
distribution  have  results  similar  to  those  of  inequalities  of  heat 
distribution  or  mosquito  distribution.  The  superheated  objects 
or  supermalarious  areas  tend  to  add  heat  or  malaria  to  the 
surrounding  objects  or  areas.  But  I  am  not  clear  that  this 
resemblance  always  holds.  Thus  the  people,  and  perhaps  the 
Anophelines,  in  the  supermalarious  patch  may,  after  a  time, 
become  so  immune  that  they  will  no  longer  add  very  much 
to  the  surrounding  ratios.  Conversely,  the  non-immunes  in 
an  inframalarious  patch  may  raise  the  ratio  there  owing  to 
"  extraneous  infection  "  (19). 

(18).    Effect    of  mass  -  migratio7is.  —  Suppose   that    a    large 


30]  EXTRANEOUS    INFECTION  205 

number  of  persons,  with  a  given  malaria  ratio,  are  suddenly 
and  simultaneously  moved  into  a  country  possessing  a  different 
malaria  ratio  :  what  will  be  the  effect  ?  Such  events  frequently 
happen,  as  when  a  regiment  of  soldiers  coming  from  England 
or  from  a  very  malarious  country  is  moved  into  a  moderately 
malarious  country ;  or  when  numbers  of  coolies  are  collected 
in  a  locality  which  has  a  different  malaria  ratio  from  that  in 
which  they  were  collected. 

The  effect  will  probably  be  that  there  will  be  an  epidemic 
in  both  cases.  An  inframalarious  regiment  of  non-immunes 
from  England  is  sure  to  suffer  to  a  degree  determined  by  the 
local  factors.  Its  own  men  will  be  the  principal  ones  to  suffer, 
but  the  numerous  fresh  cases  among  them  will  tend  to  react 
on  the  local  population.  In  the  case  of  the  introduction  of  a 
supermalarious  regiment,  the  surrounding  local  population  will 
suffer  most,  and  will  in  turn  react  on  the  men  of  the  regiment. 
In  both  cases  the  malaria  ratio  will  ultimately  tend  to  settle 
down  to  the  static  ratio  of  the  locality.  Examples  of  both 
of  these  cases  are  of  frequent  occurrence.  Large  bodies  of 
labourers  collected  for  various  kinds  of  engineering  works  are 
liable  to  cause  outbreaks,  either  among  themselves  or  among 
the  surrounding  population,  according  to  the  respective  endemic 
ratios  and  the  local  factors.  This  will  be  especially  the  case 
if  the  aggregation  of  human  beings  causes  an  actual  increase 
in  the  local  Anopheline  factor  (9).  In  such  a  case  the  aggrega- 
tion may  have  all  the  bad  effects  of  a  patch  of  high  endemicity 
described  in  the  last  subsection. 

(19).  Extraneous  infection. — By  this  I  mean  the  infection  of 
people  during  occasional  visits  outside  their  usual  habitation — 
a  very  important  case.  There  are  many  villages  the  malaria 
ratio  of  which  under  natural  conditions  would  be  low,  but  in 
which  it  is  maintained  at  an  unnaturally  high  level  by  the 
fact  that  the  inhabitants  work  in  more  malarious  areas  at 
certain  times  of  the  year.  Thus  in  the  village  of  Mazi  (575 
inhabitants),  situated  several  hundred  feet  above  the   Plain  of 


2o6  MALARIA    IN   THE   COMMUNITY  [Sect. 

Kopais  in  Greece,  I  found  malaria  infection  in  twenty  out  of 
forty  children  examined  [1906];  but  there  were  scarcely  any 
possible  breeding  -  pools  among  the  broken  hills  round  the 
village.  The  apparent  anomaly  was  easily  explained  by  the 
fact  that  every  year  nearly  the  whole  population  descends 
to  the  plain  for  the  harvesting  in  August  (the  most  malarious 
month),  and  camps  there  for  days  or  weeks  at  a  time.  As 
the  most  malarious  months  are  also  generally  those  of  the 
greatest  agricultural  activity,  extraneous  infection  is  probably 
one  of  the  principal  equalisers  of  malarial  distribution.  In 
fact,  the  result  is  the  same  if  the  factors  of  endemicity  are 
temporarily  raised  in  a  given  locality,  or  if  the  people 
temporarily  migrate  to  another  locality  where  the  factors  of 
endemicity  are  higher.  The  local  endemicity  depends  upon 
the  local  factors,  only  if  the  local  population  remains  stationary. 
Of  course  if  there  are  any  local  Anophelines  at  all,  persons 
infected  extraneously  will  tend  to  spread  the  disease  to  some 
extent  among  those  who  do  not  leave  the  locality.  Thus 
adults  infected  while  harvesting  at  a  distance  may  infect 
their  children  when  they  return  home. 

(20).  Slow  changes  zk  endemicity. — Seasonal,  annual  and 
other  variations  such  as  we  have  considered  are  constantly 
occurring  in  every  malarious  country  ;  but,  besides  these, 
certain  slow  but  persistent  changes,  sometimes  affecting  very 
large  areas,  are  often  observed,  or  at  least  reported.  It  is 
stated  that  a  whole  country  is  gradually  becoming  more 
and  more,  or  less  and  less,  malarious.  As  undeniable  examples 
I  may  quote  the  entry  and  increase  of  malaria  in  Mauritius, 
and  its  disappearance  from  Britain.  How  explain  the 
phenomena  ?  They  may  be  due,  not  to  one,  but  possibly 
to  any  or  all  the  factors  concerned  in  the  malaria  equation. 
Let  us  first  consider  each  of  the  possible  factors  in  turn. 

{a)  The  Anopheline  factor,  that  is,  the  number  of  carrying 
insects  per  person,  may  slowly  and  persistently  vary.  As 
shown   in   (15)  a  scarcely-appreciable  variation  in  this  factor 


3o]  SLOW   CHANGES  207 

may  produce  a  striking  change  in  the  endemicity.  Thus  with 
60  Anophelines  per  person  the  static  malaria  ratio  should 
stand  at  about  one-third  ;  but  it  should  stand  at  double  that 
with  the  Anophelines  at  120.  Yet  few  persons  would  be 
able  to  observe  this  difference  in  the  number  of  the  insects  ; 
and  as  no  census  has  been  taken  in  the  past,  the  scientific 
student  would  possess  no  standard  for  comparing  the  present 
with  it.  Yet  many  things  may  occur  or  concur  to  influence 
this  factor  to  a  considerable  degree. 

Thus  it  is  well  known  that  long  but  inexplicable  undu- 
lations occur  in  the  weather-cnrv&s.  These  often  affect  only 
certain  tracts  of  country,  and  have  marked  results  upon  the 
local  crops  and  prosperity.  They  may  thus  quite  possibly 
make  a  considerable  percentage  of  difference  in  the  Anopheline 
output,  besides  tending  to  influence  the  recovery  factor.  It 
would  be  difficult  to  state  precisely  what  the  exact  effect 
of  the  weather  might  be.  Excessive  rainfall  might  either 
increase  or  decrease  the  Anopheline  output,  especially  of 
certain  species,  according  to  local  breeding  conditions.  Thus 
we  should  observe  the  change  in  the  malaria  without  being 
able  to  draw  a  very  clear  correlation  curve  between  it  and 
the  weather. 

Again,  according  to  Walter  [1908],  afforestation  has  a 
marked  effect  on  the  number  of  rainy  days.  The  great 
exhalation  of  moisture  from  vegetation  tends  to  increase  the 
afternoon  thunder  showers  which  occur  so  frequently  over 
tropical  lands  (but  not  seas)  at  certain  seasons.  It  has  con- 
siderable influence  on  crops,  and  doubtless  helps  to  keep 
breeding-pools  filled.  Irrigated  cultivation  is  evidently  likely 
to  have  a  large  similar  effect,  especially  with  extensive 
irrigation  works  and  with  certain  corps.  High -class  roads 
and  railways  tend  to  obstruct  natural  surface  drainage  and 
also  to  provide  numerous  breeding-pools  in  the  "  borrow-pits " 
along  their  route  (section  57) ;  and  I  have  seen  the  undoubted 
effect  of  them  in  Sierra  Leone,  Lagos,  Panama  and  Mauritius. 


2o8  MALARIA   IN   THE  COMMUNITY  [Sect. 

But  whether  the  increase  of  total  breeding  surface  produced 
by  them  is  sufficiently  large  to  modify  the  average  Anopheline 
factor  over  a  great  area  is  another  question.  Probably 
irrigated  cultivation  has  a  larger  effect.  General  increase  of 
population  may,  by  section  29  (7),  increase  the  mosquito  out- 
put out  of  proportion  to  the  increase  of  the  human  population, 
by  supplying  more  food  to  the  female  Anophelines ;  and 
diminution  of  prosperity  may  have  the  same  result,  by  (12). 
Thus  many  things  may  modify  the  Anopheline  factor ;  and 
as  we  possess  no  exact  method  of  measuring  mosquitos  it 
will  always  be  difficult  to  decide  how  or  why  the  factor  has 
been  changed,  or  if  it  has  been  changed  at  all. 

{b)  Changes  in  the  carrying  and  biting  factors  may  occur 
as  the  result  of  a  gradual  predominance  of  certain  species  of 
Anophelines.  As  we  now  know,  the  fauna  and  flora  of  a 
country  frequently  change  to  a  considerable  extent.  Those 
originally  found  in  ocean  islands,  like  Mauritius  and  the 
Seychelles,  are  apt  to  be  almost  swamped  by  imported 
species.  Quite  possibly,  therefore,  more  "  virulent "  species 
of  Anophelines  may  gradually  increase  very  greatly  in  certain 
areas,  at  least  for  a  time  under  certain  cycles  of  weather  or 
with  certain  kinds  of  cultivation. 

{c)  Human  iuimigratioti  into  certain  areas,  especially  in 
connection  with  large  planting,  railway,  mining  or  irrigation 
works,  may  tend  to  create /^a  of  malaria  (17);  to  enhance 
the  local  rate  by  the  importation  of  cases  or  even  of  non- 
immunes; to  increase  the  convection  factors  s  and  b,  by  destitu- 
tion or  bad  housing ;  or  to  raise  the  Anopheline  output  by 
additional  food. 

id)  The  habits  of  the  people  may  change  in  consequence 
of  prosperity,  famines,  pestilences  or  increase  of  civilisation. 
Thus  they  may  use  better  houses,  or  houses  of  two  storeys, 
or  mosquito  -  nets,  or  glass  windows.  Or  a  larger  proportion 
of  medical   men   may  practise  among  them  ;   or  quinine   may 


3o]  EXAMPLES  209 

be  more  accessible  ;  or  they  may  abandon  cultivation  for  trade 
or  take  to  cities — and  so  on. 

It  will  always  be  a  very  difficult  matter  to  select  the  most 
probable  factor.  The  final  result  will  generally  be  due  to 
the  balance  of  all  the  forces,  some  pulling  this  way  and  some 
that.  S.  R.  Christophers  and  C.  A.  Bentley  have  recently 
[1909]  considered  that  a  slow  increase  in  certain  Indian  areas 
is  due  not  so  much  to  the  Anopheline  factor  as  to  (c) — that 
is,  immigration  in  connection  with  large  economic  develop- 
ments. Their  paper  is  thoughtful,  but,  unfortunately,  they  do 
not  deal  with  their  subject  quantitatively.  They  give  us  no 
estimate  of  the  degree  of  the  reputed  epidemics,  of  the  pro- 
portion of  immigrants  and  of  area  occupied  by  them  to  total 
population  and  area,  of  their  methods  of  enumerating  the 
Anophelines,  and,  indeed,  of  comparing  the  effects  of  any  of 
the  possible  factors.  It  is  evident  that  immigration  and  allied 
factors  may  have  some  results,  but  it  is  necessary  to  calculate 
/iozv  much  compared  with  those  of  other  influences.  Without 
some  attempt  at  exact  quantitative  estimates,  the  scientific 
study  of  the  diffusion  of  malaria  is  as  impossible  as  that  of 
the  diffusion  of  heat.  Many  similar  medical  papers  on  the 
subject  have  the  same  deficiency. 

(21).  Examples:  Mauritius,  Isniailia,  Clairfond,  Britain. — 
In  section  i  reasons  were  given  for  the  opinion  that  malaria 
might  have  been  comparatively  scarce,  or  entirely  absent,  in 
Greece  and  Italy  before  the  historic  period,  and  that  after 
about  550  B.C.  it  probably  increased  greatly  in  amount.  This 
theorem  can  scarcely  be  proved  ;  but  I  will  now  describe  briefly 
the  similar  events  which  have  occurred  within  the  memory  of 
living  persons  in  Mauritius  and  Reunion. 

The  island  of  Mauritius,  situated  about  550  miles  (885 
kilometres)  east  of  Madagascar,  and  lying  just  within  the 
southern  tropic,  covers  an  area  of  705  square  miles  (1,825 
square  kilometres),  rises  to  a  height  of  about  600  metres  in 
the  centre,  from  which  it  slopes  down  more  or  less  gradually 

o 


2IO  MALARIA   IN   THE   COMMUNITY  [Sect. 

to  the  sea.     The  climate  is  the  usual  tropical  marine  climate, 
warm,  equable  and  humid,  and  the  vegetation  is  rich.     Dis- 
covered in  1 507,  it  was  peopled  by  Dutch  and  then  by  French 
settlers,  who  were  always  introducing  slaves  from  Africa  and 
Madagascar.       In    18 10   it   was    taken   by   the    British.      The 
slaves    were   set    free    in    1834,   and    from    next   year   onward 
an   immense   importation    of  coolie   labour    from    India   com- 
menced and  continued.     Thus  more  than  20,000  coolies  were 
introduced   in  each  of  the  years    1843,   1854,   1858   and    1865, 
and    in    1859    no    less    than    48,377    were    imported.      Quite 
certainly  large  numbers  of  these  immigrants  must  have  been 
infected    with    malaria,    yet,    equally    certainly,    no    endemic 
malaria   occurred    in    the    island    all    this   time.       I    examined 
the  point  with  the  utmost  care  for  the  purposes  of  my  Report 
to   the   Government    [1908],   looked    through    endless    returns 
and  studied  the  voluminous   evidence  placed    before  a  Com- 
mission  of  Enquiry.      A.    Davidson    [1892]    and    many   other 
writers  have  reached   the   same  conclusion.     In  Saint-Pierre's 
classical  novel  Paul  and  Virginia  (1789)  no  mention  is  made 
of  malaria  in  the  island.     Dr  Lorans,  the  late  lamented  Medical 
Director,   who    always    lived    there,   informed    me   that    there 
was  none  when   he  was   a   boy.     At   that   time   the   planters 
and    whites    lived    in    houses    scattered    all    over   the   country, 
and  they  and  the   British    troops   and    officials  lived  entirely 
free  from  local  infection.     Relapses  of  malaria  and  other  fevers 
such    as   relapsing   fever,   were,   of  course,   noted    among    the 
immigrants,  but   the    malaria   did    not   spread,  though    a   few 
medical  men  suspected    the   existence  of  occasional  sporadic 
endemic    cases    since   (?)    1857.       In    1865,    however,   a    small 
outbreak   commenced    in  a  marshy  district   near   the   capital, 
Port  Louis.     Next  year  the  epidemic  reached  the  capital,  and 
in  1 866- 1 867   attained    alarming  proportions.     It  was  like  an 
epidemic  of  plague  or  cholera.     One  quarter  of  the  inhabitants 
of  Port  Louis  died  from  all  causes  in   1867,  and  6,224  out  of 
a   population   of  87,000   in   one    month   (April).      The   whole 


3o]  EPIDEMICS    IN    MAURITIUS  211 

death-rate  of  the  island  rose  from  32/1000  in  1866  to  120/1000 
in  1867,  the  total  population  being  360,000.  The  disease 
spread  in  two  years  all  over  the  lower  parts  of  the  island,  and 
has  remained,  and  probably  increased,  ever  since  (section  32). 
In  the  sister  island  of  Reunion,  125  miles  distant,  precisely 
similar  events  occurred  at  the  same  time.  There  also  there 
had  been  no  previous  endemic  malaria  in  spite  of  the  intro- 
duction of  slaves  from  Madagascar  and  of  Indians  from 
India. 

How  explain  this  extraordinary  and  terrible  event,  which 
shattered  existing  notions  about  malaria?  The  present  carrier 
is  P.  costalis,  an  African,  not  an  Indian  mosquito.  If  it  had 
existed  in  the  islands  in  large  numbers  the  epidemic  would 
have  commenced  long  previously — certainly  with  the  beginning 
of  the  copious  Indian  immigration,  thirty  years  before  its  actual 
commencement.  If  it  had  existed  in  small  numbers,  below 
the  endemic  limit,  it  ought  still  to  have  spread  the  disease 
to  some  extent,  according  to  the  reasoning  in  (16);  but  most 
authorities  denied  that  this  occurred  at  all  before  1865.  More- 
over, on  both  these  suppositions,  the  chances  are  that  the 
epidemic  would  not  have  commenced  simultaneously  in  both 
islands,  especially  because  the  Indian  immigration  into 
Mauritius  was  much  greater  than  that  into  Reunion.  I  can 
only  conclude,  therefore,  that  P.  costalis  was  introduced  from 
Africa  or  Madagascar  simultaneously  into  both  islands, 
probably  by  the  same  vessel,  a  year  or  two  before  the 
epidemic ;  that  it  spread  rapidly  and  soon  multiplied  over 
the  endemic  limit ;  and  that  from  this  point  the  success  and 
ultimate  permanence  of  the  malarial  invasion  was  assured. 
Of  course  the  inhabitants  would  not  be  able  to  distinguish 
the  new-comer  among  the  swarms  of  innocuous  mosquitos 
already  present,  and  there  appears  to  be  no  reason  why, 
after  being  once  introduced,  it  should  not  have  reached  the 
endemic  limit  of  numbers  in  a  year  or  two.  This  therefore 
appears  to  be  wholly  a  case  of  the   Anopheline  factor.     The 


212  MALARIA   IN   THE   COMMUNITY  [Sect. 

human  factors  had  been  present  for  at  least  thirty  years 
without  causing  the  disease. 

A  similar  case  is  that  oi  Isviailia  (section  53).  Situated  on 
the  Suez  Canal  in  the  desert,  it  remained  free  from  malaria  until 
the  fresh-water  canal  was  completed  in  1877,  when  malaria 
appeared  almost  immediately.  Since  then  the  disease  con- 
tinued to  increase  with  fluctuations,  until  it  was  banished  in 
1902  by  proper  mosquito  reduction.  Here  again  the  outbreak 
was  probably  due  almost  entirely  to  the  Anopheline  factor. 

A  more  difficult  case  is  that  of  an  outbreak  in  the 
neighbourhood  of  Clairfojid  Marsh  in  Mauritius  (section  30 
(i)  map),  already  frequently  mentioned.  This  marsh  existed 
on  a  plain  1,400  feet  (427  metres)  above  sea-level,  and  the 
epidemic  is  described  in  my  Report  [1908]  by  Dr  de  Chazal 
who  had  been  practising  in  the  neighbourhood  since  1890, 
and  by  myself,  and  also  by  Major  Fowler  [1908].  The  history 
is  as  follows  : — 

Before  1903  Dr  de  Chazal,  who  lived  not  far  from  the  marsh, 
had  observed  a  few  cases  of  malaria,  but  only  among  Indians. 
In  that  year,  however,  cases  began  to  occur  among  well-to-do 
people  living  in  the  neighbourhood,  and  the  epidemic  now 
developed  rapidly.  The  cases  at  the  neighbouring  dispensary 
were  as  follows  : — 

1904  1905  1906  1907 

346  843  1,147  1,487 

and  similar  rises  in  the  cases  of  malaria  at  seven  other 
dispensaries,  situated  not  far  away,  also  occurred.  In  1906 
the  British  soldiers  in  barracks  (see  subsection  i)  began  to 
be  affected.  In  1908  Major  Fowler  and  I  witnessed  an 
epidemic  of  seventy-one  cases  in  January  among  these  troops, 
and  on  making  a  house-to-house  visitation,  found  a  spleen 
rate  of  241/339=71%,  and  an  average  spleen  of  4-12  among 
the  Indian  children  living  round  the  marsh.  The  disease  was 
being  carried  by   P.  costalis,  which  our  "  moustiquiers "  found 


3o]  MALARIA   IN    BRITAIN  213 

with  considerable  difficulty,  and  not  by  M.  mauritianus  which 
abounded  round  the  marsh.  The  marsh  was  now  drained  by 
the  Government  ;  quinine  was  simultaneously  distributed  in 
the  houses  by  ourselves  and  a  dispenser;  and  the  epidemic 
ceased. 

How  explain  it?  The  marsh  had  been  there  as  long  as 
any  one  could  remember,  and  P.  costalis,  though  it  prefers  sea- 
level,  had  probably  been  breeding  in  it  in  small  numbers  all 
the  time.  Indians  as  well  as  the  richer  classes  had  been  living 
near  at  hand,  and  imported  cases  had  certainly  been  common. 
Why,  then,  did  not  the  epidemic  commence  before?  Up  to 
ig02  the  population  round  the  marsh  had  been  comparatively 
scarce,  but  in  that  year  a  great  increase  of  Indians  took  place 
owing  to  the  advent  of  a  regiment  of  Sepoys,  and  many  of 
these  Indians  built  huts  close  to  the  marsh  waters.  Here,  then, 
might  be  a  case  of  creation  of  a  focus  of  high  endemicity  ;  but 
still  I  find  it  difficult  to  explain  the  focus  without  supposing  an 
increase  in  P.  costalis, pari  passu  with  that  of  the  human  popula- 
tion. The  case  is  most  probably  explained  by  an  increase  due 
to  more  abundant  food  in  the  new  huts  built  close  to  the  marsh, 
according  to  sections  29  (7)  and  30  (9  and  12) ;  and  possibly  by 
an  increase  in  the  biting  factor,  due  to  the  growth  of  the  village 
nearer  to  the  marsh. 

The  disappearance  of  malaria  from  Britain  has  been  ably 
described  by  G.  H.  F.  Nuttall,  L.  Cobbett  and  T.  Strangeways- 
Pigg  [1901].  The  observers  made  a  careful  study  of  the  former 
distribution  of  the  disease  in  Britain,  and  of  the  present  dis- 
tribution of  the  Anophelines.  The  two  coincided  to  some 
extent — that  is,  the  malaria  was  within  the  Anopheline  area, 
but  not  so  extensive.  The  disease,  formerly  severe,  began  to 
decline  early  last  century,  but  still  lingered  on  until  about  1850. 
I  was  "clinical  clerk"  in  St  Bartholomew's  Hospital  in  1879 
to  a  woman  with  greatly  enlarged  spleen  and  characteristic 
fever,  who  lived  in  the  Fen  Country  and  had  never  been  out 
of  England.      Since   that   time   endemic  malaria  has  entirely 


214  MALARIA   IN   THE  COMMUNITY  [Sect. 

vanished  from  Britain,  with  the  exception  of  two  cases  among 
soldiers  (footnote,  section  14).^ 

The  three  British  AnopheHnes  are  A.  maculipennis,  A. 
bifurcatus  and  A.  nigripes.  They  are  all  capable  of  carrying 
malaria,  but  Theobald  thinks  that  the  first  will  not  bite  man 
in  Britain.  The  authors  conclude  that  the  disappearance  of 
malaria  has  been  due  {a)  to  reduction  of  AnopheHnes  by 
drainage ;  {b)  to  reduction  of  population  by  emigration  ;  and 
ic)  to  the  use  of  quinine.  I  think  that  {h)  is  not  sound.  The 
disappearance  is  almost  certainly  due  to  the  reduction  of  the 
Anopheline  factor  by  drainage  below  the  endemic  limit,  even 
in  the  Fen  Country,  and  also  to  enhancement  of  the  recovery 
factor  by  the  more  general  use  of  quinine.  I  wonder,  however, 
whether  there  has  been  any  change  in  climate,  and  also  whether 
glass  windows  have  been  used  more  since  the  beginning  of 
last  century. 

Many  other  examples  might  be  cited,  but  the  reader  will 
doubtless  prefer  to  consider  them  for  himself. 

(22).  Possible  errors  in  the  study  of  endejnicity. — One  is  very 
apt  to  find  the  local  endemicity  too  high  in  comparison  with 
the  local  number  of  AnopheHnes  to  be  found  in  houses.  In 
1897,  in  an  intensely  infected  plantation  near  Ootacamund, 
India,  I  found  during  several  visits  only  one  Anopheline  (the 
first  I  ever  saw),  although  I  searched  the  houses  myself  and 
offered  the  people  rewards — and  this  was  at  the  height  of  the 
malaria  season.  In  fact  there  were  so  few  mosquitos  of  any 
kind  that  I  began  to  doubt  the  whole  mosquito  theory  (just 
before  the  discovery  of  the  zygotes).  The  local  carriers  were 
probably  "  wild  "  mosquitos  which  I  did  not  know  how  to  look 
for;  or  else  I  may  have  missed  the  principal  hatching-out 
season.  At  Clairfond  ten  trained  "  moustiquiers  "  could  procure 
only  a  few  P.  costalis  every  night.     We  must  never  assume, 

^  Sir  Cliftord  AUbutt  tells  me  that  he  saw  numerous  cases  in  Cambridge  in  i860. 
Nuttall,  Cobbett  and  Strangeways-Pigg  verified  a  case  at  Norwich  in  1898  [1901, 
P-  31]- 


3o]  SOURCES    OF   ERROR  215 

without  clear  proof,  that  the  number  of  insects  seen  or  caught 
during  a  few  hours'  or  days'  search  affords  any  exact  measure 
of  the  number  actually  present  during  that  period — still  less  of 
the  number  which  may  be  present  at  other  periods. 

It  is  often  observed  that  the  malaria  ratio  is  high  where 
there  appears  to  be  little  breeding-surface — that  "  dry  "  places 
seem  often  to  be  more  malarious  than  "  wet "  ones.  But  we 
have  no  right  to  assume  that  the  carriers  always  breed  more 
in  the  deep  or  permanent  pools  which  constitute  "  water- 
logging "  than  in  the  shallow,  evanescent  rain-pools  which  are 
often  the  only  waters  found  in  the  dryer  areas.  The  latter 
may  perhaps  give  a  much  larger  output  at  the  proper  season 
than  the  former  can  yield  all  the  year  round  (sections  29  (8) 
and  30(1)). 

In  some  cases  the  Anopheline  factor  is  probably  truly 
below  what  we  might  expect  from  the  malaria  ratio  ;  but  such 
cases  may  be  due  to  extraneous  infection  (19),  or  to  immigra- 
tion from  neighbouring  areas  of  high  endemicity  (16,  17). 

Statements  are  frequently  made  to  the  effect  that  though 
the  number  of  Anophelines  in  a  locality  is  large  the  malaria 
ratio  is  small — as,  for  instance,  the  case  reported  by  Celli  [1902]. 
Here  again  we  must  not  assume  that  the  number  of  Anophelines 
actually  found  during  a  few  days  is  an  exact  measure  of  those 
existing  all  the  year  round.  We  have,  perhaps,  done  the 
counting  just  at  the  moment  when  the  insects  happened  to 
abound.  Or,  on  comparing  two  localities,  we  may  have  been 
concerned  with  a  domestic  species  or  variety  in  the  locality 
where  the  insects  appeared  to  be  more  numerous,  and  a  wild 
species  or  variety  in  the  other  locality.  Even  where  it  is 
proved  by  continued  observation  that  the  Anophelines  do  really 
average  a  high  figure  where  there  is  little  malaria,  this  will 
merely  suggest  that  some  of  the  other  factors  are  unsuitable  ; 
for  example,  the  local  insects  may  belong  to  an  immune  strain. 
Thus  we  have  never  succeeded  in  infecting  the  A.  niaculipcnnis 
round  Liverpool  from  infected  sailors. 


2i6  MALARIA   IN   THE  COMMUNITY  [Sect. 

In  fact  those  who  pretend  to  study  the  correlation  between 
the  AnopheHne  factor  and  the  malaria  rate  are  very  prone 
to  make  two  mistakes  :  (a)  they  often  fail  to  consider  deeply 
enough  the  principles  involved,  and  (b)  they  are  apt  to  base 
startling  "  discoveries  "  on  quite  insufificient  random-sampling — 
an  error  into  which,  according  to  Professor  Karl  Pearson, 
medical  men  frequently  fall.  So  far  as  the  human  reason 
enables  us  to  judge,  there  must  be  some  correlation  between 
the  two  quantities.  When,  therefore,  we  are  told — as  we 
frequently  are,  especially  in  India  —  that  so-and-so  has  not 
observed  any  such  correlation,  we  naturally  look  for  the 
detailed  figures  of  his  investigations ;  and  when  we  find,  in 
place  of  these,  mere  statements  of  opinions  and  impressions, 
we  naturally  infer  that  it  is  not  the  principles  which  are 
worthless,  but  the  observations.  A  person  who  thinks  to 
settle  such  difficult  questions  merely  by  running  from  village 
to  village,  catching  a  few  Anophelines  and  examining  a  few 
people,  can  have  little  knowledge  of  the  nature  of  scientific 
evidence.  To  yield  any  worthy  results  at  all,  the  enquiry 
would  demand  the  most  careful  and  continuous  study  of  all 
the  factors  concerned  (sections  29  (4),  and  31). 

A  mistake  frequently  made  is  to  suppose  that  there  must 
be  some  correlation  between  the  number  of  Anophelines  exist- 
ing on  a  given  day  and  the  total  percentage  of  infected  persons. 
But  the  former  will  tend  to  influence  only  the  inoculation  rate 
of  the  future.  The  total  percentage  of  infected  persons  will 
depend  upon  past  factors  which  may  no  longer  exist.  They 
are  often,  or  generally,  connected,  but  not  necessarily  always  so. 

Equal  errors  may  be  made  regarding  the  measurement  of 
human  malaria.  For  example,  the  disease  is  often  supposed 
to  be  specially  prevalent  among  soldiers,  coolies  or  prisoners  ; 
but  this  may  be  merely  a  statistical  error,  due  to  the  fact  that 
these  classes  are  under  more  careful  supervision  than  the  general 
public  is. 

{2^.  I  have  attempted  to  examine  as  carefully  as  possible 


3i]  OTHER   POSSIBLE   FACTORS  217 

the  principal  factors  concerned  in  the  spread  of  malaria,  but 
may  have  overlooked  several  of  importance.  The  effect  of 
immunity,  both  among  men  and  Anophelines,  deserves  much 
closer  study.  So  also  do  many  questions  connected  with 
difference  of  species  of  the  parasites.  It  is  by  no  means 
certain  that  immunity  against  one  species  confers  much  or 
any  against  another.  If  this  is  the  case,  many  epidemics  may 
be  caused  merely  by  the  entry  of  a  species  not  hitherto  pre- 
valent in  a  locality ;  and  the  simultaneous  prevalance  of  all 
three  species  may  lead  to  a  much  more  serious  fever  rate. 
Koch  observed  [1900]  that  comparative  immunity  against 
quartan  seems  to  have  little  effect  against  the  other  parasites  ; 
but  I  am  not  sure  that  reaction  against  an  existent  invasion 
in  a  person  will  have  very  much  effect  against  a  new  infection 
even  by  the  same  species. 

The  effect  on  the  local  malaria  rate  of  desertion  of  marshy 
areas  (9)  should  be  similar  to  that  of  drainage,  and  must  not 
be  forgotten  though  it  is  not  often  witnessed.  Conversely, 
the  effect  of  approximation  to  a  marsh,  as  when  people  come 
and  settle  near  one  (for  example,  the  Clairfond  outbreak  just 
described),  should  be  similar  to  the  effect  of  increase  of  marsh. 
Obviously  it  will  come  to  the  same  thing  if  we  bring  a  marsh 
close  to  human  habitations,  or  bring  human  habitations  close 
to  a  marsh. 

31.  The  Measurement  of  Malaria;— In  section  26  I  gave 
definitions  of  the  terms  malaria  rate,  endemicity,  and  inoculation 
rate.  We  have  now  to  consider  how  these  and  other  estimates 
can  best  be  obtained  for  a  given  population  inhabiting  a  given 
area.  Note  to  begin  with  that  we  can  never  obtain  any  such 
rates  exactly ;  and  also  that  the  degree  of  approximation  to 
the  truth  must  always  depend  on  the  amount  of  time  and 
labour  we  have  to  spare  for  the  task. 

Our  estimates  may  be  of  two  kinds,  actual  or  comparative. 
Comparative   estimates  are  those  which  seek   to  compare  the 


2i8  MALARIA   IN   THE  COMMUNITY  [Sect. 

proportion  of  infected  persons  in  the  same  locality  at  different 
times,  or  in  different  localities  at  the  same  time.  It  may 
often  be  much  easier  to  obtain  comparative  than  actual 
estimates. 

Let  us  consider  first  the  different  possible  methods,  and 
then  the  respective  values  of  them. 

(i).  The  parasite  rate  and  index. — By  malaria  rate  or  ratio 
I  mean  the  percentage  or  proportion  of  people  who  really 
contain  living  plasmodia  at  some  given  moment — not  those 
who  show  symptoms.  By  parasite  rate  I  mean  the  same 
thing.  Now  in  section  i8  (8)  and  (9)  it  was  shown  that 
an  average  man  contained  about  3,000,000  c.mm.  of  blood, 
and  that  a  quarter  of  an  hour  is  required  to  examine 
1/50  of  a  c.mm.  under  the  microscope.  Thus  in  that  time 
we  can  search  only  1/ 150,000,000th  of  a  man's  blood.  In  other 
words,  if  there  are  less  than  150,000,000  parasites  in  the 
patient's  blood  the  chances  are  that  we  may  not  find  one, 
even  after  a  quarter  of  an  hour's  search.  Hence  we  can  never 
hope  to  ascertain  with  certainty  whether  a  single  patient  does 
or  does  not  contain  plasmodia,  and  can  therefore  certainly 
never  discover  the  actual  parasite  rate  of  any  number  of  people. 

By  parasite  index  I  mean  the  percentage  of  persons  in 
whose  blood  plasmodia  are  found  after  fifteen  minutes'  ^  search 
— that  is,  of  persons  who  contain  more  than  about  50  plasmodia 
to  I  c.mm.  To  ascertain  even  this  is  a  laborious  task,  requiring 
for  100  people  twenty-five  hours'  continuous  work. 

Obviously  the  parasite  index  must  always  be  less  than 
the  parasite  rate.  What  ratio  will  the  latter  bear  to  the 
former?  We  do  not  know.  Out  of  100  infected  persons 
perhaps  only  60  or  70  may  contain  more  than  50  plasmodia 
per  I  c.mm.  of  blood  at  a  given  moment.  But  this  is  a  mere 
guess,  and  no  accurate  studies  have  been  made  on  the  point. 
The  ratio  certainly  varies  largely,  but  as  we  do  not  know  it 
with  certainty,  the  parasite  index  gives  no  exact  inform^ation 

^  Some  authors  are  satisfied  with  five  or  ten  minutes'  search. 


3i]  THE   PARASITE   INDEX  219 

regarding  the  actual  parasite  rate.  It  gives  valuable  informa- 
tion, however,  on  one  point.  Every  person  in  whom  parasites 
are  found  is  certainly  infected.  Hence  the  parasite  index 
gives  at  least  the  viinimuni  possible  percentage  of  infected 
persons — that  is,  we  know  that  the  actual  parasite  rate  cannot 
be  lower  tha^i  the  parasite  index. 

For  comparative  estimates  the  parasite  index  is  still  more 
useful,  because  in  them  we  deal  only  with  ratios  from  time 
to  time  or  from  place  to  place.  Thus  if  it  has  varied  from 
say  20^  to  55^  in  two  large  aggregates  of  persons  examined, 
we  may  infer  that  the  actual  parasite  rate  has  varied  to  a 
similar  amount.  We  do  not  know  what  that  actual  parasite 
rate  was,  with  the  parasite  index  either  of  20%  or  of  55%, 
but  we  conclude  that  its  variation  has  been,  ceteris  paribus, 
similar — that  is,  from  20%  to  55//. 

As  originally  observed  by  Koch  and  Stephens  and 
Christophers,  confirmed  by  Ziemann,  Plehn,  Annett,  and 
Button  and  many  workers,  the  parasite  index  varies  greatly 
according  to  age,  being  generally  highest  in  children  (9). 
Hence  comparative  estimates  must  be  based  on  a  study  of 
persons  of  the  same  age.  Race,  quinine  treatment,  and  social 
status  seem  also  to  have  considerable  effect. 

The  method  is  open  to  several  sources  of  fallacy.  The 
skill  of  the  observer  may  make  a  difference  of  say  20%  or 
more  in  the  results  obtained  ;  and  the  time  employed  in  the 
search  for  plasmodia  is  very  important.  In  1906  I  obtained 
a  number  of  slides  of  blood  from  Greek  children,  and  since 
then  these  slides  have  frequently  been  given  for  study  to  the 
classes  of  the  Liverpool  School  of  Tropical  Medicine.  On 
every  occasion  that  this  has  been  done,  one  or  more  of  the 
students  have  discovered  parasites  in  specimens  in  which  they 
had  not  been  previously  found !  In  making  exact  comparative 
estimates  it  is  therefore  necessary  to  employ  observers  of  the 
same  skill,  and  to  fix  the  time  during  which  the  search  must 
be  made. 


220  MALARIA    IN   THE   COMMUNITY  [Sect 

But  the  principal  weakness  of  the  method  is  due  to  the 
fact  that,  owing  to  the  labour  involved,  only  a  comparatively 
small  number  of  people  can  be  examined — so  that  the  error 
of  random  sampling  is  likely  to  be  very  large.  Thus,  suppose 
that  we  have  examined  50  specimens  for  15  minutes  each, 
costing  12-5  hours'  work  (exclusive  of  collecting  and  staining), 
and  have  found  plasmodia  in  25  specimens,  we  have  no  right 
to  infer  that  the  parasite  index  of  all  the  people  in  the  locality 
will  be  50%.  The  chances  are,  by  Poisson's  formula  (8),  that 
if  we  examine  another  50  persons  we  may  find  parasites  in  any 
proportion  of  them  from  30%  to  70% — the  error  being  20%. 
Thus,  if  the  same  observer,  using  precisely  the  same  methods, 
examines  50  different  persons  on  two  occasions,  and  finds 
25  infected  on  the  first  occasion  and  35  infected  on  the  second 
occasion,  he  still  has  no  right  to  assume  that  the  actual 
parasite  rate  {i.e.,  the  malaria  rate)  of  the  locality  has  risen 
between  the  two  examinations. 

The  method  is  probably  capable  of  much  improvement  by 
quicker  means  of  microscopic  diagnosis  (sections  65  (i)  ). 

(2).  The  spleen  rate  and  index. — This  method  has  been  in 
use  for  a  long  time.  We  know  that  the  spleen  enlarges 
sufficiently  to  be  detected  by  palpation  in  a  considerable 
proportion  of  infected  persons.  Such  enlargement  is  dis- 
coverable with  certainty  and  in  a  few  seconds  by  the  fingers 
pressed  under  the  ribs  of  the  left  side,  and  any  one — hospital 
assistants,  nurses  and  laity  —  can  detect  it.  The  persons  to 
be  examined  are  passed  in  a  line  before  the  examiner,  while 
another  person  records  the  results ;  and  with  good  manage- 
ment 100  people  can  be  thus  inspected  in  an  hour.  Or  else 
we  can  do  the  work  by  house-to-house  inspection.  In  section  22 
I  gave  the  results  of  a  "spleen  census"  of  31,022  children  in 
Mauritius,  and  of  92,258  children  in  Ceylon — so  that  very  large 
numbers  of  people  can  be  studied  by  this  method.  It  is  open 
to  the  following  defects : — 

{a)  The  enlargement  may  be  so  slight  in  a  small  proportion 


3i]  THE   SPLEEN    INDEX  221 

of  cases,  especially  early  infections,  that  it  may 
be  overlooked  in  them  if  we  use  palpation  only. 
Generally,  however,  there  is  fever,  or  a  history  of 
recent  fever,  in  such  cases. 

{b)  The  spleen  of  healthy  infants  is  sometimes  so  easily 
palpable  that  the  unskilled  observer  may  think  that 
it  is  enlarged, 

{c)  Not  all  infected  persons  show  palpable  splenomegaly. 

{d)  Not  all  splenomegalous  persons  are  necessarily  infected. 

{e)  Other  diseases,  such  as  kala-azar  and  various  anaemias, 
cause  splenomegaly  (section  22) ;  but  the  former  is 
limited  to  certain  tracts  of  country,  and  the  latter 
are  too  scarce  to  affect  large  statistics.  Generally 
speaking,  widespread  splenomegaly  is  due  to 
malaria. 

The  advantages  of  the  method  are  : — 

{a)  That  the  enlargement  can  be  detected,  practically  with 
certainty  and  in  a  few  seconds,  by  almost  any  one. 

{b)  That  the  method  can  be  applied  with  little  trouble  to 
enormous  numbers  of  people,  thus  practically  avoid- 
ing the  error  of  random  sampling. 

I  have  never  known  rupture  of  spleen  to  follow  palpation  ; 
but  the  possibility  of  this  must  be  remembered. 

We  must  note  that  a  smaller  degree  of  splenic  enlargement 
can  be  detected  by  pe^xussion  (as  practised  by  medical  men) 
than  merely  by  palpation.  By  the  former  method  we  can  nearly 
always  detect  some  enlargement  in  malaria.  Thayer  [1898] 
claims  that  it  always  occurs.  Mannaberg  says  [1905]  that  out 
of  132  cases  of  different  types,  "cachexias  omitted,"  he  found 
it  in  all  but  one  case — in  15  cases  (11*4^  of  total)  by  per- 
cussion alone,  and  in  116  (88%)  by  palpation  also.  Thus  the 
finer  art  of  percussion  added  nearly  one-eighth  more  to  the 
number  of  cases  disclosed  by  palpation.  Laveran  agrees  as  to 
the   frequency  of  this  symptom,  but  other  authors  give  lower 


222  MALARIA    IN   THE   COMMUNITY  [Sect. 

percentages.  It  is  probably  often  a  question  of  care  in 
examination.  Among  sailors  treated  at  the  Royal  Southern 
Hospital  of  Liverpool,  palpable  enlargement  is  not  very 
frequent.  Many  writers  give  percentages  without  actuals — 
that  is,  nearly  worthless  figures.  L.  M.  Hope  [1904],  in  a 
study  of  1784  cases,  microscopically  verified  at  Pabna,  Northern 
Bengal,  states  that  in  374,  or  20%,  the  spleen  was  not  palpable  ; 
but  .she  does  not  state  whether  the  remaining  cases  were  studied 
by  percussion.  In  102  Greek  children  examined  by  me  (4),  the 
spleen  was  palpable  in  48,  and  parasites  were  found  in  12  which 
showed  no  enlargement  (by  palpation  only).  Probably,  careful 
percussion  would  have  disclosed  some  enlargement  in  all  of 
these  cases.  On  the  whole,  then,  I  think  we  should  conclude 
that  some  degree  of  splenic  enlargement  probably  exists  in 
95-100%  of  all  persons  infected  with  malaria ;  but  that  the 
enlargement  \s,  great  enough  to  be  palpable  only  in  about  75-90/^. 

The  reader  should  note  this  difference  between  enlargements 
detectable  by  palpation  or  by  percussion  only.  In  public  health 
work,  which  demands  the  examination  of  large  numbers  of 
people  in  order  to  avoid  error  of  random  sampling,  careful 
percussion  is  not  generally  practicable,  or,  at  least,  practised. 

Thus  by  the  term  splenic  index,  I  generally  mean  the  per- 
centage of  persons  in  whom  enlargement  is  detectable  by 
palpation  only. 

In  order  to  determine  the  spleen  rate  accurately,  it  is 
necessary  to  use  careful  percussion  on  all  persons  in  whom  no 
enlargement  has  been  found  by  palpation.  If  such  persons  are 
numerous  this  may  add  considerably  to  the  time  required  for 
the  investigation — say  two  or  three  minutes  for  each  person. 

Another  important  point  has  to  be  considered.  We  have  no 
right  to  assume  that  the  parasites  are  still  present  in  all  the 
cases  of  enlarged  spleen,  especially  in  the  older  cases  with  large 
chronic  splenomegaly.  Such  cases  may  have  become  parasite- 
free  by  establishment  of  natural  immunity ;  but  we  can  never 
know  in  how  many  the  parasites  have  absolutely  vanished,  or 


3i]  COMBINED   PARASITE   AND    SPLEEN    INDEX  223 

have  only  declined  in  numbers  below  the  limit  at  which  we  can 
readily  find  them. 

In  what  proportion  of  persons  with  enlarged  spleen  are  there 
no  Plasmodia  at  all  ?  It  is  impossible  to  say  ;  but  we  may  give 
20^  as  a  rough  conjectural  estimate. 

Suppose,  then,  that  20%  of  persons  with  parasites  have  no 
palpable  enlargement  of  the  spleen,  and  that  20%  of  those 
with  palpable  enlargement  of  the  spleen  have  no  parasites — or, 
at  any  rate,  that  the  two  percentages,  whatever  they  may  be, 
are  about  equal.  It  then  follows  that  the  palpable  spleen  rate, 
or  splenic  index,  will  give  a  nearly  exact  measure  of  the  per- 
centage of  infected  persons — that  is,  of  the  actual  malaria  rate 
of  the  locality.  But  at  present  this  theorem,  which  would  be 
one  of  great  practical  importance,  is  based  only  on  conjectural 
estimates. 

Lastly,  we  must  note  that  the  spleen  index  is  probably 
modified  considerably  by  local  conditions,  quinine,  and  the 
age  of  the  people  examined  (sections  22  and  31  (9)). 

(3).  Combined  parasite  index  and  spleen  index. — If  we  have 
time  we  can  use  the  parasite  index  and  spleen  index  combined. 
The  people  should  be  divided  into  four  classes :  ia)  those 
without  enlarged  spleen  or  detectable  parasites  ;  {b)  those  with 
both  ;  and  {c)  and  id)  those  with  one  but  not  the  other.  Thus 
out  of  102  children  examined  in  Greece,  we  found  : — 


Moulki 

Parasites 
only. 

5 

Spleen 
only. 

23 

Parasites 
and  spleen. 

12 

Nil. 
22 

Total 
62 

Mazi    . 

7 

4 

9 

20 

40 

Total    .12  27  21  42  102 

Now  if  we  use  the  term  endemic  index  (section  26)  to  denote 
the  percentage  of  persons  in  whom  malaria  is  diagnosed  by  a7ty 
method,  then  the  endemic  index  of  Moulki  at  that  time  was 
40/62=64-5%,  and  of  Mazi  was  20/40=50%.  Provided  that  we 
know  that  the  splenomegaly  is  due  only  to  malaria,  and  also 
have  time  to  work  out  the  parasite  index,  this  combined  method 


224  MALARIA   IN  THE   COMMUNITY  [Sect. 

is  obviously  more  exact  than  either  method  by  itself.  Thus 
in  both  these  villages  together,  the  parasite  index  by  itself 
was  only  33/102  =  32^,  and  the  spleen  index  by  itself  only 
48/102  =  47%;  while  the  combined  methods  give  a  general 
endemic  index  of  60/102=59%. 

It  is  important  to  note  that  in  this  example,  while  the  cases 
with  enlarged  spleen  numbered  48,  those  with  parasites,  but 
without  enlarged  spleen,  numbered  12,  or  1/4  of  the  spleen 
cases.  If  this  proportion  applies  generally,  the  endemic  index 
will  be  found  by  adding  25%  to  the  spleen  cases.  (This  figure 
is,  however,  too  high  by  the  results  of  Mannaberg  and  Hope 
just  quoted.) 

Again,  the  cases  with  parasites  numbered  33,  while  those 
with  spleen  but  without  parasites  numbered  27,  or  9/ 11  of 
the  parasite  cases.  If  this  proportion  holds  generally,  the 
endemic  index  will  be  found  by  adding  82%  to  the  parasite 
cases. 

It  would  thus  seem  that  the  spleen  index  is  much  nearer 
the  truth  than  the  parasite  index — provided  that  the  spleno- 
megaly is  really  due  only  to  the  malaria. 

Lastly,  we  observe  that  the  figures  both  at  Moulki  and  at 
Mazi  are  too  small  to  enable  us  to  make  exact  comparative 
estimates  of  the  malaria  rate  of  each  village ;  and  we  should 
probably  have  done  better  if  we  had  abandoned  the  parasite 
index  and  had  spent  the  time  at  our  disposal  in  examining  the 
spleen  of  every  person  in  the  villages.  Moulki,  on  the  plain  of 
Kopais,  contained  350  people,  and  Mazi,  several  hundred  feet 
above  the  plain,  contained  575  people.  The  figures  were 
obtained  in  May  to  June  [1906],  at  the  beginning  of  the  malaria 
season. 

The  number  of  persons  with  parasites  hit  without  spleno- 
megaly seems  to  me  an  important  figure,  because  such  cases 
are  probably  due  to  recent  infections,  before  the  spleen  has  had 
time  to  become  enlarged — especially  in  children.  There  were 
no   less   than    12/102=11-8%   of   such   in   these   two   villages, 


3i]  AVERAGE  ENLARGED  SPLEEN  225 

suggesting  that  the  spring  infections  had  already  commenced. 
The  weather  was  hot,  and  A.  maculipennis  plentiful. 

(4).  Average  spleen  and  average  enlatged  spleen. — By  the 
parasite  index  and  spleen  index,  or  by  both  combined,  we 
attempt  to  estimate  the  percentage  of  infected  persons  in  a 
locality ;  but  further  information  can  be  obtained  by  recording 
the  degree  of  enlargement  found.  For  this  purpose  I  suggested 
in  Mauritius  [1908]  a  figure  which  I  call  the  average  spleen 
(section  22).  The  observer  notes  whether  the  size  of  the  spleen, 
as  roughly  estimated  by  palpation,  is  unity,  or  about  three  times, 
six  times  or  nine  times  the  normal  size  —  these  sizes  being 
called  normal,  or  small,  medium  or  great  enlargements.  He 
then  multiplies  the  number  of  persons  found  to  possess  each 
class  of  enlargement  by  i,  3,  6,  or  9  as  the  case  may  be,  adds 
the  products  together,  and  divides  by  the  total  number  of 
persons  examined.  Thus  in  Mauritius  we  found,  out  of  30,137 
children  of  fifteen  years  and  under. 


Normal  spleens 
Small  enlargements 
Medium  enlargements 
Great  enlargements 

Total 


19,711 

4,381 

3,479 
2,566 

30.137 


Thus  the  average  spleen  for  children  in  the  island  works  out  at 
2'54  times  the  normal  size. 

Another  figure,  which  I  call  the  average  enlarged  spleen,  is 
found  in  the  same  manner,  but  without  considering  the  normal 
spleens  ;  that  is,  multiply  the  small  enlargements  by  3,  the 
medium  enlargements  by  6,  the  great  enlargements  by  9,  add 
the  results,  and  divide  by  the  total  number  with  enlarged 
spleen.  In  the  above  example,  the  average  enlarged  spleen 
was  5'48.  Obviously,  according  to  the  rough  standards  pro- 
posed, this  figure  must  always  lie  between  3  and  9. 

These  estimates  require  a  little  more  time  to  obtain  than 
the  simple  spleen  index,  and  should  generally  be  attempted 
only  by  medical  men.     I  think  that  one  minute  a  person  will 


226  MALARIA   IN   THE   COMMUNITY  [Sect. 

suffice.  The  information  given  is  more  detailed,  but  also  more 
open  to  error,  since  different  observers  may  have  different 
ideas  as  to  what  constitute  small,  medium  or  great  enlarge- 
ment respectively. 

The  degree  of  enlargement  probably  depends  considerably 
upon  the  factors  given  in  section  22 — racial,  social  and  climatic 
factors,  and  age  and  treatment  of  the  sick.  That  is,  two  popula- 
tions with  the  same  actual  proportion  of  infected  persons  may 
have  different  average  enlarged  spleens,  the  difference  depending 
on  these  factors. 

The  average  spleen  depends,  not  only  on  the  degree  of 
enlargement,  but  also  on  the  proportion  of  infected  persons 
(general  malaria  rate),  and  may  be  looked  upon  as  an  index 
of  the  average  amount  of  illness  caused  by  malaria  in  the 
community.  The  average  enlarged  spleen  indicates  only  the 
degree  of  enlargement  where  it  exists.  Several  useful  deduc- 
tions may  be  drawn  from  the  figures.  Thus  numerous  small 
enlargements  would  tend  to  indicate  many  recent  infections  ; 
and  numerous  large  ones  with  few  small  ones,  a  past  epidemic. 
The  comparative  figures  for  Mauritius  may  be  taken  for  a 
standard,  as  malaria  has  prevailed  constantly  there  since  1866. 
The  species  of  parasite  may  have  considerable  influence 
on  the  degrees  of  enlargement.  C.  F.  Craig  [1909]  thinks 
that  the  malignant  parasites  produce  most  enlargement ;  but 
L.  M.  Hope  [1904]  found  that  in  43  great  enlargements 
malignant  parasites  occurred  in  10,  benign  tertian  in  9,  and 
quartan  in  32  (some  of  the  infections  being  mixed). 

The  study  of  the  splenic  enlargement,  so  important  for 
public  health  work,  has  been  curiously  neglected  in  medical 
literature. 

(5).   The  fever  rate  and  index. — By  fever  rate  (daily,  monthly, 

annual)   I    mean   the   percentage   of  persons  who  really  have 

malarial  fever  during  a  given  period  ;  by  fever  index,  I  mean 

the  percentage  of  those  who  have  been  ascertained  to  have  it. 

The   index    must   be   always   lower   than   the    rate.     Even 


3i]  THE    FEVER    INDEX  227 

with  soldiers,  gaol  prisoners  and  indentured  coolies  the  most 
careful  supervision  would  be  required  to  detect  all  the  slighter 
cases.  Among  troops  the  bad  custom  still  remains  of  enter- 
ing in  the  books  only  the  more  severe  cases — which  are  said 
to  be  admitted  to  hospital,  while  the  slighter  cases  are  only 
detained.  This  quite  falsifies  the  malaria  statistics,  and  is  due 
only  to  bad  administration.  Besides  this,  many  soldiers  disdain 
to  come  to  hospital  for  slight  attacks.  If  this  is  the  case  among 
these  classes,  then  we  can  imagine  how  difficult  it  would  be  to 
estimate  the  fever  rate  among  a  large  civil  population. 

If  we  could  do  so,  however,  we  should  have  a  fairly  exact 
measure  of  the  malaria  rate  —  since  every  infected  person 
probably  suffers  more  or  less  from  illness  during  at  least 
some  part  of  his  infection.  But  we  have  no  measure  of  the 
ratio  between  the  rate  and  the  index.  Probably  the  former 
is  often  two  or  three  times  the  latter,  even  in  the  case  of 
troops. 

But,  while  it  gives  little  exact  information  regarding  the 
actual  malaria  rate,  the  fever  index  is  still  useful.  The 
admissions  into  military  hospitals,  civil  hospitals  and  hospitals 
of  gaols  and  plantations,  are  generally  fairly  correctly  diagnosed 
by  medical  men,  and  give  some  idea  of  the  great  amount  of 
sickness  caused  by  the  disease.  The  same  is  true  of  the  large 
number  of  attendances  for  malaria  at  out-patient  departments 
and  dispensaries.  The  figures  are  valuable  for  comparative 
estimates  of  variation  from  time  to  time  or  place  to  place. 

Both  for  admissions  and  attendances,  the  actual  numbers 
of  patients  admitted  or  attending  any  hospital  are  not  very 
useful,  as  they  may  be  influenced  by  the  popularity  or  accessi- 
bility of  the  institution ;  but  the  ratio  of  admissions  or 
attendances  for  malaria,  compared  with  those  for  all  causes, 
is  always  important,  not  only  for  comparative  estimates,  but 
because  it  shows  the  relative  importance  of  malaria  compared 
with  all  other  diseases.  It  gives  us  some  basis  for  fixing  the 
proportion  of  the  public  funds  which  should  be  expended  on 


228  MALARIA   IN  THE   COMMUNITY  [Sect. 

the  prevention  of  the  former,  according  to  the  general  sanitary 
principle  enunciated  in  section  38  (4),  namely,  that  that  propor- 
tion should  depend  on  the  relative  importance  of  the  various 
diseases. 

For  example,  in  Mauritius  during  the  seven  years  1900- 
1906  we  had  the  following  figures : — 

Average  population 384,676  a  year. 

Average  admissions  for  all  causes    .         .       18,761      „ 
Average  admissions  for  malaria  alone      .         4,348      „ 

Thus  malaria  caused  nearly  one-quarter  (2  3"2%)  of  the  total 
admissions.  Moreover,  in  the  year  1907  alone  there  were 
79.053  attendances  for  all  causes  at  all  the  hospitals  and 
dispensaries  in  the  island,  and  of  these  28,294,  or  3 5 "8%,  were 
reported  as  due  to  malaria. 

This  is  an  example  of  the  general  law  that  the  attendances 
for  malaria  are  greater  than  the  admissions  (in  comparison  to 
total  attendances  and  admissions).  Obviously  only  the  more 
severe  cases  of  fever  seek  admission  into  hospital,  and  a  much 
larger  proportion  of  all  malaria  cases  content  themselves  with 
mere  attendance  for  advice  and  medicine. 

In  India  in  1901  (before  quinine  was  much  given),  out  of 
300,847  troops  and  prisoners  108,860,  or  36-2%,  were  admitted 
for  malarial  fevers  ;  and  these  admissions  constituted,  according 
to  the  official  figures,  37%  of  the  admissions  for  all  causes.  I 
take  this  year  at  random  ;  and  it  will  be  seen  on  inspection  of 
similar  statistics  in  most  tropical  countries  that  similar  figures 
hold  roughly  from  place  to  place  and  time  to  time  in  most  of 
them. 

As  a  very  broad  general  rule  we  may  state  that  in  most,  or 
at  least  many,  malarious  countries  about  one-third  of  the  total 
population  considered  require  medical  treatment  for  malaria 
every  year ;  and  also  that  malaria  is  responsible  for  about  one- 
third  of  the  total  attendances  at  hospitals  and  dispensaries.  Or, 
to  be  still  more  general,  we  may  put  both  these  ratios  at  some- 
thing between  one-quarter  and  one-half 


31]  THE   CONSTANTLY-SICK    INDEX  229 

Of  course,  error  in  diagnosis  vitiates  the  figures  to  some 
extent.  Thus  many  cases  of  fever  are  not  malarious  at  all, 
but  may  simply  be  classed  under  that  heading  by  careless 
or  overworked  observers.  The  symptoms  of  the  disease  are, 
however,  so  well  marked  that  I  doubt  whether  the  total  error 
produced  in  this  manner  is  really  very  large — say  over  5%. 
On  the  other  hand,  the  error  of  random  sampling  for  the 
purpose  of  obtaining  a  parasite  index  is  often  very  much 
larger. 

M.  Watson  (section  57)  has  used  hospital  statistics  well  for 
showing  the  comparative  fall  of  the  malaria  rate  in  drained 
areas.  While  the  admissions  from  the  drained  areas  fell 
rapidly,  those  from  the  surrounding  undrained  territories  con- 
tinued as  before. 

The  clinical  thermometer  may  be  used  more  than  it  is  for 
estimating  the  endemic  index.  It  could  easily  be  employed 
together  with  examination  of  the  blood  and  the  spleen. 

(6).  The  constantly -sick  rate  and  index. — By  these  terms  we 
mean  the  average  proportion  of  people  who  are  actually  ill 
with  malarial  fever  at  a  given  moment — or  who  are  found  to 
be  ill  (index).  Thus  in  India  in  1901,  out  of  60,838  European 
troops,  on  the  average  666,  or  i'09%,  were  always  ill  with 
malaria  —  that  is,  almost  the  effective  strength  of  a  whole 
regiment.  In  Mauritius,  Dr  Bolton,  Medical  Officer  of  the 
Immigration  Department,  estimated  for  me  that  during  the 
malaria  season  in  the  most  malarious  sugar  plantations  as 
many  as  20%  of  the  total  male  adult  population  may  be 
sick  from  malaria  alone  on  one  day.  As  the  malaria  season 
is  often  also  the  busiest  agricultural  season,  such  a  figure  means 
an  enormous  loss  of  labour. 

These  estimates  are  important  because  they  afford  some 
measure  of  the  economic  loss  due  to  the  disease.  Thus  in  India 
in  1901  the  European  troops  lost  666x365  =  243,090  working 
days  during  the  year,  besides  loss  due  to  death  and  invaliding, 
and  loss  of  capacity  for  war.     But  as  a  rule  the  estimates  can 


230  MALARIA   IN   THE   COMMUNITY  [Sect. 

be  obtained  only  for  troops,  coolies  of  factories  and  plantations, 
and  prisoners.  For  the  general  population  we  can  have  no 
definite  figures,  and  can  only  calculate  them  on  the  basis  of 
the  former  classes. 

The  average  duration  of  a  case  can  be  obtained   from  the 
constantly  -  sick    index    (or    vice    versa)    from    the    following 
formula : — 
Admissions  x  average  duration  =  constantly  sick  x  days  in  year. 

In  India  the  average  duration  of  a  case  of  intermittent  fever 
among  European  troops  is  about  two  weeks,  and  of  remittent 
fever  about  four  weeks ;  but  this,  of  course,  means  only  the 
residence  of  the  men  in  hospital,  and  takes  no  note  of 
relapses.  The  figures  will  be  found  in  Table  IV  of  the 
Indian  statistics. 

(7).  Malarial  death-rates. — In  most  malarious  countries 
medical  certificates  giving  the  cause  of  death  are  not  demanded. 
Hence  in  such  countries  the  public  statistics  are  not  reliable 
as  regards  the  cause  of  the  mortality — that  is,  we  can  have 
no  confidence  in  the  number  of  deaths  attributed  to  malaria 
in  the  tables.  We  can  often,  however,  obtain  valuable  informa- 
tion by  calculation  from  the  figures  of  general  mortality ;  but 
this  subject  requires  to  be  dealt  with  separately  (section  32). 
(8).  Random  sampling. — Nothing  has  caused  more  mistakes 
in  the  literature  of  malaria,  and  indeed  of  most  medical  and 
sanitary  subjects,  than  ignorance  of  the  great  error  in  reasoning 
which  may  be  caused  by  insufficient  random  sampling. 

Suppose  that  we  desire  to  ascertain  some  general  law 
regarding  a  large  number  of  objects.  Then  the  only  exact 
way  to  ascertain  the  law  would  be  to  examine  all  the  objects. 
Suppose,  however,  that  we  have  no  time  to  do  this  ;  then  we 
must  content  ourselves  with  the  attempt  to  ascertain  the  law 
approximately  by  examining  samples.  We  must  take  the 
samples  quite  at  random,  and  must  examine  enough  of  them. 
Obviously,  if  the  total  number  of  objects  is  large,  we  shall 
obtain    no    correct    deduction    by    examining    only    one,   two, 


3i]  RANDOM   SAMPLING  231 

three  ...  of  them.     The  more  of  them  we  examine  the  nearer 
we  shall  come  to  the  exact  truth. 

Suppose,  for  example,  that  we  wish  to  ascertain  the  pro- 
portion of  leucocytes  in  a  patient  which  belong  to  the  mono- 
nuclear variety.  We  may  be  very  far  from  the  truth  if  we 
examine  only  two  or  three  leucocytes  ;  nearer  if  we  examine 
twenty  or  thirty,  or  two  or  three  hundred,  and  still  nearer  if 
we  examine  two  or  three  thousand  ;  but  we  can  obtain  the 
exact  truth  with  certainty  only  if  we  examine  all  the  leucocytes 
in  his  body. 

So  also  if  we  wish  to  know  the  parasite  index  in  a  locality 
— that  is,  the  percentage  of  people  in  whom  plasmodia  can 
be  found  after,  say,  quarter  of  an  hour's  search.  If  we  examine 
only  two  or  three  persons  we  may  be  very  far  from  the  truth ; 
we  shall  come  nearer  and  nearer  to  the  truth  by  examining 
more  and  more  of  the  people ;  but  we  can  obtain  the  exact 
truth  with  certainty  only  by  examining  every  person  in  the 
locality. 

If  we  have  time  to  examine  only  some  of  the  people  we 
can  obtain  only  an  approximation  to  the  truth.  It  is  a  gross 
error  in  science,  and  yet  one  which  is  very  frequently  made, 
to  suppose  that  this  approximation  is  the  truth  itself. 

Take  for  example  the  case  mentioned  in  (i)  above.  Suppose 
that  there  are  10,000  people  in  a  place,  and  that  out  of  50 
people  examined  we  have  found  the  parasites  in  25.  Then 
we  are  quite  truthful  when  we  say  that  the  parasite  index  of 
the  50  people  examined  is  50% ;  but  if  we  presume  to  argue, 
on  the  strength  of  this  small  random  sampling,  that  the 
parasite  index  of  the  whole  locality,  containing  10,000  people, 
is  50%,  we  make  a  gross  scientific  error,  and  say  what  may 
be  absolutely  untrue — what,  in  fact,  may  be  not  even  near 
the  truth.  Similarly,  if  we  try  to  estimate  the  number  of 
Anophelines  in  this  locality  by  counting  them  in  only  a  few 
houses  we  may  make  another  error  equally  gross.  Lastly,  if, 
after  making  two  such  errors,  we  next  proceed  to  argue  that 


232  MALARIA   IN   THE   COMMUNITY  [Sect. 

there  was  no  relation  between  the  parasite  index  and  the 
number  of  AnopheHnes  in  the  locality,  we  may  perhaps  come 
to  a  wrong  conclusion  ;  but,  whether  our  conclusion  is  right 
or  wrong,  we  shall  certainly  convict  ourselves — well,  not  exactly 
of  scientific  competence ! 

This  error  is  frequently  made  tacitly  in  medical  literature 
by  recording  only  percentages,  without  giving  the  actual 
number  of  objects  examined.  For  example,  an  observer  says 
that  40%  of  a  patient's  leucocytes  were  mononuclears,  or  that 
20%  of  the  people  in  a  place  showed  plasmodia,  without 
stating  how  many  total  leucocytes  or  people  were  examined. 
Such  statements  have  no  meaning  whatever — except  that  the 
man  who  makes  them  is  ignorant  of  this  simple  law  of  reason- 
ing. A  reader  cannot  judge  the  value  of  a  writer's  deductions 
unless  he  knows  the  actual  facts  from  which  those  deductions 
were  drawn.  Where  a  writer  merely  gives  a  percentage  in 
this  manner,  we  cannot  be  sure  whether  he  has  not  deduced 
it  from  a  study  of  only  a  few  objects.  But  we  are  sure  of 
something  else,  namely,  that  he  is  not  acquainted  with  the 
methods  of  accurate  reasoning,  and  are  therefore  forced  to 
doubt  the  value  of  all  his  deductions.  It  is  necessary  to  make 
these  somewhat  severe  remarks,  if  only  in  the  hope  of  saving 
the  waste,  occasioned  by  this  common  mistake,  of  otherwise 
excellent  work. 

The  reader  will  now  remark  that  it  is  impossible  to  examine 
all  the  leucocytes  in  a  patient's  body,  or  all  the  people  in 
a  large  district.  How  many  must  we  examine  in  order  to 
approach  sufficiently  near  to  the  truth  ?  This  question  belongs 
to  the  domain  of  statistical  science  and  cannot  be  discussed  at 
length  here ;  but  it  is  advisable  to  give  the  well-known  Poisson 
formula  for  statistical  error,  with  an  addition  made  by  Professor 
Karl  Pearson,  the  amended  formula  being  particularly  useful 
for  the  measurement  of  malaria. 

Let  N  be  the  total  number  of  objects,  such  as  all  the 
leucocytes  in  a  patient's  body  or  all  the  people  in  the  locality 


3i]  ERROR   OF   RANDOM   SAMPLING  233 

under  consideration.  Let  n  be  the  number  of  these  actually 
examined  (say  200  leucocytes  or  persons) ;  and  let  /  be  the 
number  of  these  found  during  the  examination  to  belong  to  a 
special  class — suppose  that/ =100  mononuclear  leucocytes  or 
persons  found  to  contain  plasmodia.  Then  p\n  will  be  the 
corresponding  ratio  among  the  objects  examined — that  is,  it 
will  be  1/2,  or  50^,  in  the  examples  referred  to.  But  we  have 
no  right  to  infer  that  the  same  ratio  will  hold  for  all  the  N 
objects  under  consideration.  Let  e  denote  what  is  called  the 
error,  and  ^^  the  percentage  of  error.  Then  by  the  Poisson- 
Pearson  formula, 


o/_200    l2p{n-p)    I        n-\ 


Examining  this  formula,  we  shall  see  that  when  n  =  N,  that 
is,  when  we  examine  all  the  objects  under  consideration,  the 
factor  i—{n—  i)j(N'—  i)  =  o,  and  the  whole  error  vanishes  ;  that 
is,  we  obtain  the  exact  truth.  But  if  n  is  small  compared  with 
N,  this  factor,  and  therefore  the  error,  becomes  larger.  If  A^ 
is  very  great,  as  when  we  are  considering  all  the  leucocytes  in 
a  patient  or  all  the  people  in  a  large  district,  the  same  factor 
approximates  to  unity,  making  the  error  large — unless  n  can 
be  correspondingly  increased. 

Thus  if,  out  of  200  leucocytes  examined,  100  are  found  to 
be  mononuclears,  then,  since  N  is  very  large,  (;?—  i)/(iV—  i)  =  o  ; 
so  that  ^%=^ioo=io.  That  is,  the  error  is  10%.  We  might 
have  inferred,  after  finding  100  mononuclears  out  of  200  leuco- 
cytes examined,  that  the  same  proportion  (50%  mononuclears) 
would  have  held  for  all  the  leucocytes  in  the  patient's  body.  But 
we  have  no  justification  for  this  assumption.  The  probability 
is  that  if  we  examine  another  200  leucocytes,  the  proportion 
in  this  second  batch  may  be  anything  between  SO%+io%  and 
50%— 10%,  that  is,  may  vary  from  60%  to  40%.  All  that  we 
can  infer,  then,  from  the  small  sample  of  leucocytes  examined 
by  us,  as  to  the  exact  truth  regarding  all  the  leucocytes  in 


234 


MALARIA   IN   THE   COMMUNITY 


[Sect. 


the  patient,  is  that  the  percentage  of  mononuclears  probably 
lies  between  60%  and  40% — a  very  different  thing  from  the 
5°%  which  we  might,  ignorantly,  have  assumed  to  be  the 
proportion. 

Now  suppose  that  we  have  to  deal  with  a  village  of 
800  people,  and  that  we  have  examined  200  for  plasmodia 
and  have  found  these  in  100  of  them.  Here  the  factor 
I -(;«— i)/(iV— i)  =  about  3/4,  and  the  other  factors=io  as 
before.  Hence  ^^=  5^3  =  8*65.  Thus,  while  the  parasite  index 
of  the  200  people  actually  examined  is  50%,  that  of  the  800 
people  in  the  village  may  be  anything  from  5o+8"65%  to 
50-8-65%;  that  is,  from  58-65%  to  41-35%. 

Suppose,  however,  that  in  the  same  village  we  had  examined 
only  40  persons  (as  a  recent  Indian  writer  recommends)  and 
had  found  plasmodia  in  20.  Then  the  percentage  of  error 
—  5n/i9==2i-8,  and  the  parasite  index  of  the  village  will  not 
be  50%,  as  the  unwary  student  might  imagine,  but  anything 
between  71-8%  and  28-2% — a  very  ambiguous  result.  Yet  we 
are  often  asked  to  accept  important  theories  on  figures  like 
these. 

The  following  square  roots  may  be  useful  : — 


Square 

root  of  2=i*4i 

Square  root  of  12  =  3-46 

3=1-73 

13  =  3-60 

5  =  2-24 

14  =  3-74 

6  =  2-45 

15  =  3-87 

7  =  2-64 

„             17  =  4-12 

8  =  2-83 

„             18  =  4-24 

,          10  =  3-16 

19  =  4-36 

11  =  3-32 

„             20  =  4-47 

The  error  tends  to  be  larger  when  the  percentage  of 
objects  belonging  to  the  particular  class  is  near  50%  of  the 
total  number  of  objects  examined,  than  when  it  is  a  low  or 
high  percentage.  We  must  therefore  examine,  for  example, 
more  leucocytes  to  obtain  the  percentage  of  mononuclears  than 
to  obtain  that  of  eosinophiles ;  and  more  people  if  the  parasite 


3i]  AGE   AND   THE    MALARIA   INDEX  235 

or  spleen  index  is  near  50%  than  if  they  are  very  small  or  very 
large. 

(9).  Variation  of  the  malaria  index  according  to  age. — It  is 
now  generally  accepted  that  amongst  the  natives  of  a  per- 
manently malarious  locality  the  signs  of  infection — parasites, 
fever,  enlarged  spleen — are  generally  much  more  frequently 
found  in  children  than  in  adults.  From  this  we  infer  that  the 
individual  can  acquire  natural  immunity  against  the  disease. 

So  far  as  I  can  ascertain,  this  fundamental  law  was  first 
discovered  and  stated  by  C.  W.  Daniels  as  the  result  of  his 
study  of  a  large  number  of  autopsies  in  British  Guiana 
[1895].  He  found  that  the  frequency,  not  only  of  simple 
enlargement  of  the  spleen,  but  also  of  the  malarial  pigmenta- 
tion of  the  organ,  varied  from  age  to  age.  Both  enlargement 
and  pigmentation  were  absent  in  the  bodies  of  infants  less  than 
one  month  of  age ;  became  more  and  more  frequent  in  bodies 
of  children  up  to  five  years  of  age,  in  about  80%  of  whom 
they  occurred  ;  and  then  became  progressively  less  frequent 
with  advancing  age.  These  results  were  obtained  from  1,289 
autopsies  on  natives  of  the  colony  or  of  other  malarious 
places  —  mostly  negroes  and  East  Indians.  But  different 
figures  were  recorded  from  205  autopsies  on  persons,  chiefly 
negroes,  who  were  born  in  non  -  malarious  places,  and  had 
come  to  the  colony  in  early  adult  life.  In  nearly  all  of 
these  the  symptoms  occurred  shortly  after  arrival,  and  then 
fell  in  frequency  with  age,  but  never  to  so  low  a  figure  as 
in  the  case  of  the  natives.  The  following  are  the  curves  for 
the  negroes  and  East  Indians.     (See  page  236). 

Daniels  remarked,  "  It  is,  I  think,  clear  from  these  figures 
that  malaria  is,  amongst  those  exposed  (to  it)  from  childhood, 
a  disease  of  early  life.  ...  In  adult  life,  amongst  them,  it  is 
rare ;  whilst  amongst  persons  of  the  same  race,  but  not 
exposed  in  childhood,  it  is  common  in  adult  life.  This,  it 
seems  to  me,  can  point  to  only  one  conclusion,  viz. :  that 
immunity  is  acquired  by  a  class  (that  is,  natives)  in  the  course 


3i]  AGE   AND   THE    MALARIA   INDEX  237 

of  exposure  to  the  infection  in  this  district  for  some  twenty 
years ;  and,  from  the  evidence  of  its  frequency  (evidence 
persisting  for  variable  periods,  in  some  cases  for  years),  that 
this  immunity  is  probably  acquired  by  previous  attacks." 
Daniels  also  observed  that  the  spleen  is  frequently  found  to 
be  enlarged,  and  very  much  enlarged,  without  showing  any 
pigmentation  at  all,  and  inferred  from  this  that  there  might 
be  some  other  cause  besides  malaria  for  the  enlargement. 

In  my  study  of  kala-azar  [1899]  I  came  to  the  erroneous 
conclusion  that  it  was  nothing  but  severe  chronic  malaria. 
Arguing  from  Daniels's  observations,  I  thought  that  the  un- 
pigmented  enlargement  of  the  spleen  in  this  disease  was  due 
to  numerous  previous  attacks  of  malaria  followed  by  partial 
immunity  and  natural  elimination  of  the  pigment  (plasmodin). 
Kala-azar  is  now  known,  of  course,  to  be  caused  by  another 
parasite  ;  but  I  still  think  that  the  pigment  may  be  eliminated 
in  cases  of  malaria  after  the  parasites  have  died  out — thus 
explaining  its  absence  from  old  malarial  enlargements. 

A  little  later,  R.  Koch  observed  that  the  parasites  can 
usually  be  found  more  frequently  in  children  than  in  adults, 
and  suggested  the  examination  of  the  blood  for  measuring 
malaria.  His  figures  are  given  principally  in  his  third  Report 
[April  1900].  At  Stephansort,  out  of  734  persons  the  parasites 
were  found  in  157,  or  21-4%.  In  Kaiser- Wilhelm-Land,  at 
Bogadjim,  out  of  22  children  of  under  five  years,  the  parasites 
were  found  in  13,  or  59^ ;  while  none  were  found  in  86  persons 
of  over  five  years  in  age.  At  Bongu,  out  of  19  children  under 
five  years,  the  parasites  were  found  in  12,  or  63^;  out  of  17 
children  from  five  to  ten  years,  in  4,  or  24% ;  and  out  of  39 
persons  from  ten  to  forty-five  years,  in  none  (note,  large  error 
of  random  sampling). 

Almost  at  the  same  time,  Christophers  and  Stephens 
published  similar  figures  regarding  studies  in  the  Gold  Coast 
[June  1900].  They  state  that  in  four  places  the  parasite  index 
found  by  them  was  90,  75,  71  and  23%  among  "  babies" ;  57,  50, 


238  MALARIA   IN   THE   COMMUNITY  [Sect. 

75,  20%  among  children  up  to  eight  years;  28,  (?),  30,  (?)%  in 
children  up  to  twelve  years  ;  while  children  over  twelve  years 
showed  parasites  very  rarely.     They  give  no  actuals. 

During  the  same  year,  Annett,  Button  and  Elliott  made  a 
survey  of  the  parasite  index  in  ten  places  in  Nigeria  [1902]. 
The  collected  results  were  as  follows : — 


Ages 

O-I 

1-2 

2-3 

3-4 

4-5 

5-6 

6-7 

7-8 

No.  examined 

n 

46 

49 

47 

41 

23 

30 

25 

No.  infected   . 

10 

29 

31 

24 

20 

8 

2 

II 

Percentage 

27 

63 

63 

51 

49 

35 

7 

27 

Ages 

8-9 

9-10 

10  + 

0-5 

5-10 

10  + 

Total 

No.  examined 

16 

14 

40 

220 

108 

40 

363 

No.  infected    . 

4 

•^ 

4 

114 

27 

4 

145 

Percentage 

25 

14 

10 

52 

25 

ID 

40 

The  figures  agree  well  with  those  of  pigmented  spleen  rates 
given  by  Daniels.  There  is  a  curious  drop  at  the  6-^  age.  The 
authors'  tables  are  well  compiled ;  but  the  numbers  for  the 
separate  localities  are  too  small  to  furnish  definite  results, 

Panse  [1902]  gives  the  following  figures  for  Tonga,  East 
Africa : — 

Ages        .    o-\      i-i       I      2      3      4-5      6-7    ^^^^"  Adults     Total 
o  -       -  J       t  J  /    grown. 

No.  examined      16         9        25     20     28      48         84      314       1,683        2,227 

No.  infected    .6        6       22     17     25      34         52      125         258  545 

Percentage      •     37      67       88     85     89     71         62        39  15  25 

Craig  gives  for  Camp  Stotsenburg,  Philippines  [1909] : — 

Ages 1-5  5-10  10-15  Adults  Total 

No.  examined  ....  40  54  53  45  192 

No.  infected     ....  30  20  13  28  91 

Percentage       •        •        ■         •  72  37  24  62  47 

Similar  figures  are  furnished  by  various  authors,  but  the 
number  of  children  examined  is  generally  too  small  to  yield 
reliable  results.  Often  only  percentages,  which  are,  of  course, 
almost  useless,  are  given. 

The  comparative  frequency  of  enlarged  spleen  in  children 
has  been  known  for  a  long  time — certainly  in  India;  but  much 
more  exact  work  on  the  subject  remains  to  be  done. 

Craig   well    remarks   [1909]    that   there   are   certain   "rules 


3i]  AGE   AND   THE   MALARIA   INDEX  239 

governing  immunity."  In  heavily  infected  localities,  where 
nearly  all  the  natives  are  probably  infected  and  re-infected  in 
childhood,  nearly  all  the  survivors  must  be  partially  immune  in 
adult  age.  On  the  other  hand,  where  only  a  smaller  propor- 
tion of  the  natives  become  infected  in  childhood,  many  of  the 
remainder  may  be  attacked  for  the  first  time  at  later  ages. 
This  must  be  especially  the  case  where  there  are  seasons,  such 
as  a  sharp  winter  or  a  hot  dry  season,  during  which  infection 
ceases.  I  notice,  for  instance,  that  the  law  of  Daniels  is  not 
much  insisted  upon  by  Italian  workers. 

From  these  considerations  an  important  deduction,  exactly 
opposite  to  the  common  opinion,  may  be  drawn.  Where  there 
is  much  malaria,  so  many  of  the  native  adults  will  be  immune 
that  few  of  them  should  show  signs  of  infection  ;  and,  conversely, 
where  the  adults  are  frequently  attacked,  the  amount  of  malaria 
should  be  comparatively  slight.  In  other  words,  if  the  malaria 
index  amongst  adults  (parasites,  fever,  splenomegaly)  is  high,  the 
malaria  rate  of  the  locality  is  probably  low  ;  and  where  the  adult 
hidex  is  low,  the  rate  is  probably  either  high  or  low.  If,  there- 
fore, a  considerable  number  of  adults  are  coming  to  hospital 
with  fever  or  enlarged  spleen,  we  should  believe,  not  that  the 
malaria  rate  of  the  population  is  usually  high,  but  that  it  is 
usually  low — comparatively,  of  course.  If  malarial  immunity 
were  complete,  and  if  every  one  were  infected  in  childhood,  no 
one  would  be  ill  afterwards.  For  example,  if  many  soldiers  in 
a  regiment  are  attacked,  we  may  infer  that  they  have  not  been 
recruited  from  very  malarious  districts. 

Unfortunately,  however,  we  are  not  sure  {a)  how  far  immunity 
derived  from  a  single  infection  protects  against  subsequent  infec- 
tions, and  {b)  how  far  immunity  against  one  species  of  parasite 
protects  against  other  species.  Thus  many  partially-immune 
adults  may  suffer  from  short  attacks  of  fever  due  to  re-infection, 
especially  by  parasites  of  a  species  different  to  the  one  to  which 
they  have  become  habituated. 

Practically,  therefore,  for  the  purpose  of  the  measurement  of 


240  MALARIA   IN   THE   COMMUNITY  [Sect. 

malaria,  it  is  best  to  consider  only  the  malaria  index  among 
children.  Among  adults  the  malaria  index  cannot  yield  very 
definite  results  :  if  high,  it  indicates  that  the  malaria  rate  is 
comparatively  low ;  if  low,  that  the  malaria  rate  is  either  very 
high  or  very  low. 

The  study  of  large  numbers  of  children  is  required  to 
establish  the  age  at  which  the  malaria  index  is  highest.  Most 
of  the  figures  suggest  that  that  age  is  between  one  and  three 
years.  Similar  studies  are  required  to  determine  the  age  of 
maximum  average  spleen,  and  of  maximum  enlarged  spleen. 

(lo).  Determination  of  the  inoculation  rate. — According  to 
section  26,  the  malaria  rate  of  a  locality  is  the  percentage  of  the 
people  who,  at  the  moment  of  enquiry,  contain  plasmodia.  But 
as  many  of  these  people  must  have  been  inoculated  weeks, 
months  or  years  previously,  the  malaria  rate  does  not  directly 
inform  us  as  to  what  is  going  on  at  that  moment — it  instructs 
us  regarding  the  past  rather  than  the  present.  We  may  wish  to 
know  how  many  people  are  actually  being  inoculated  during 
the  week,  month  or  year  of  observation  ;  and  if  we  can  ascer- 
tain this  we  can  obtain  a  measure  of  the  actual  nialariousness 
of  the  locality  at  the  moment  when  we  are  investigating  the 
malaria  in  it. 

This  could  be  ascertained  experimentally  if  we  could  dis- 
tribute throughout  the  population  a  large  number  of  healthy, 
non-immune  immigrants,  and  could  then  observe  accurately 
how  many  of  them  become  infected  within  a  given  period  :  or 
if  we  could  observe  a  large  number  of  non-immune  immigrants, 
and  learn  how  long,  on  the  average,  they  remain  healthy.  Such 
studies  can  sometimes  be  made  with  adults ;  but,  unfortunately, 
Nature  herself  is  always  carrying  out  the  experiment  for  us  by 
providing  a  constant  influx  of  non-immune  babies,  and  we  have 
only  to  ascertain  the  proportion  of  them  which  have  become 
infected  within  a  week,  month  or  year  after  birth. 

In  his  original  article  [1895],  Daniels  stated  that  in  43 
infants  who  had  died  under  one  month  after  birth  pigmentation 


3i]  THE   INOCULATION    RATE  241 

of  the  spleen  could  not  be  found  ;  that  it  occurred  in  I2"5%  of 
16  infants  of  one  to  six  months  of  age,  in  iiy  of  14  infants  of 
six  to  twelve  months,  and  in  50%  of  1 1  infants  of  one  to  two 
years  of  age.  From  these  figures  we  gather  that  in  British 
Guiana  at  that  time  the  chances  were  small  that  infection  should 
occur  within  one  month,  and  increased  by  about  2^  roughly  for 
every  month  after  birth — so  that  the  chances  were  that  about 
50%  of  all  newcomers  would  become  infected  in  two  years. 
Meanwhile,  however,  immunity  would  tend  to  reduce  the  cases. 
Of  course,  with  such  small  actuals,  the  error  of  random 
sampling  is  very  large. 

R.  Koch  in  his  third  Report  [1900]  states  that  in  nine 
localities  in  Java,  the  parasites  were  found  in  6y,  or  11^,  out 
of  619  infants  of  under  one  year  examined  ;  and  in  47,  or  8"i^, 
out  of  574  children  of  over  one  year  of  age. 

The  infantile  malaria  index  can  easily  be  obtained  by  the 
parasite  test  or  spleen  test,  or  both  combined,  and,  with  large 
actuals,  will  give  a  good  direct  measure  of  the  inoculation  rate. 
But  it  will  be  still  more  useful  if  compared  with  rates  calculated 
according  to  sections  27  and  28. 

As  before,  let  p  be  the  total  population,  and  m  and  m^  the 
proportion  of  infected  persons  at  the  beginning  and  the  end  of 
the  enquiry  respectively.  Then  at  the  beginning  of  the  enquiry 
there  were  nip  infected  persons  and  {\—iii)p  healthy  ones. 
Now  let  rnip  be  the  number  of  infected  persons  who  recover 
during  the  enquiry — suppose  that  r=\l^  and  that  the  enquiry 
lasts  one  month;  and  let  I{i—m)p  be  the  number  of  healthy 
persons  who  become  infected  during  the  enquiry.  Then  by 
section  28,  equation  4, 

m^p  =  mp  +  /( I  —  in)p  —  rmp 
or,  /( I  —  m)p  =  in^p  —  mp  +  rmp 

Thus  suppose  that,  in  a  village  of  1,000  people,  there  were 
250  infected  persons  at  the  beginning  of  the  month  and  300 
infected  persons  at  the  end  of  it.  Then,  obviously,  though 
50   infected   persons   recovered   during   the   month,  there  was 

Q 


242  MALARIA   IN   THE   COMMUNITY  [Sect. 

nevertheless  an  increase  of  50  infected  persons  at  the  end  of 
it;  so  that  100  healthy  persons  must  have  become  infected 
during  the  month.     That  is,  I{\  —  ni)p  —  \oo. 

Here  I={nt~^  —  m-\-rin)j{i—m),  and  is  the  inoculation  ratio; 
that  is,  it  gives  the  proportion  of  people,  healthy  or  unhealthy, 
inoculated  during  the  enquiry.  In  the  above  example  /=  10/75 
=  0'i33.  Out  of  the  750  originally  healthy  people  in  the 
village  100  were  newly  infected,  and  out  of  the  250  previously 
infected  people  33  were  reinfected  {Imp  gives  the  number  of 
reinfections);  so  that  altogether  133  persons  out  of  1,000  were 
inoculated  during  the  month.  The  inoculation  rate  of  the 
village  was  /x  100=  13*3%;  that  is,  the  chances  of  a  new- 
comer in  the  village,  or  of  a  new-born  child,  becoming  infected 
during  the  month  was  as  13*3  to  100. 

From  equation  i  of  section  27,  we  might  infer  roughly  that 
there  were  about  106  Anophelines  to  each  person  in  this  village. 
In  fact,  on  comparing  that  and  the  following  section,  we  see 
that  /=  b^saint. 

The  fractions  m,  m^,  I  and  r  are  connected  by  the  equation 
m^  =  m  +  I{i—m)  —  rm;  and  if  we  can  ascertain  any  three  of 
them  we  can  calculate  the  fourth — which  enables  us  to  com- 
pare observed  and  calculated  estimates.  If  the  malaria  is 
static,  so  that  nt-^  =  m,  then  I{i—vi)  =  rm.  We  may  now  esti- 
mate /  from  the  infantile  malaria  index,  w  from  the  general 
malaria  index,  and  r  from  statistics,  and  check  our  results  by 
comparison.  Suppose,  for  example,  that  r=  1/5  a  month,  and 
that  4%  of  the  infants  are  infected  in  a  month  ;  then  the 
general  infection  rate  of  the  locality  should  be  about  i6-6%. 
Comparing  these  figures  with  observed  estimates,  we  shall 
probably  arrive  nearer  to  the  truth  than  if  we  had  relied  on 
calculation  or  observation  only. 

(11).  Practical  conclusions. — Having  considered  the  various 
methods  of  measurement  which  may  theoretically  be  adopted, 
it  remains  for  us  to  select  the  best  ones  for  practical  use. 

A.  First  suppose  that  we  wish  to  form  an  Actual  Estimate 


31]  PRACTICAL   CONCLUSIONS  243 

of  the  Malaria  Rate  ;  that  is,  of  the  percentage  of  people  who 
contain  plasmodia  at  the  moment  of  observation.  We  may 
employ  {a)  the  parasite  index,  {b)  the  spleen  index,  and  {c)  the 
combined  methods. 

{a)  The  parasite  index  gives  exact  information  only  as  to 
the  lowest  proportion  of  infected  persons.  The 
proportion  of  those  who  contain  plasmodia  in 
numbers  too  few  to  be  found  during  the  time 
allotted  for  the  test  may  be  very  considerable, 
and  has  not  been  correctly  estimated.  The  test 
requires  a  skilled  observer,  and  the  expenditure  of 
so  much  time  that  it  can  be  applied  only  to  com- 
paratively few  people.  The  error  of  random 
sampling  is  therefore  generally  very  large. 
{b)  The  spleen  index  (by  palpation  only)  can  be  quickly 
ascertained,  by  almost  any  intelligent  person,  for 
large  numbers  of  people  —  so  that  the  error  of 
random  sampling  may  often  be  reduced  nearly 
or  really  to  zero.  A  certain  proportion  of  infected 
persons  have  no  palpable  enlargement  of  the  spleen, 
and  possibly  in  others  with  palpable  enlargement 
(especially  with  great  enlargement)  the  parasites 
may  have  died  out  in  consequence  of  immunity ; 
but  by  the  penultimate  paragraph  of  (2),  these  two 
sources  of  error  (amounting  to  say  20%  each)  will 
tend  to  annul  each  other,  so  that  the  spleeji  index 
should  be  a  nearly  correct  measure  of  the  true  malaria 
rate.  Quinine,  local  conditions  and  other  diseases 
(especially  kala-azar)  may  affect  the  spleen  index, 
but  in  most  countries  probably  only  to  a  small 
extent.  Percussion  of  those  who  show  no  palpable 
enlargement  will  reveal  a  greater  proportion  of 
cases ;  but  with  this  test  the  infected  non-spleen 
ratio  will  not  be  balanced  by  the  non-infected  spleen 
ratio — so  that  percussion  may  give  a  ratio  further 


244  MALARIA   IN   THE   COMMUNITY  [Sect. 

from  the  truth  than  that  given  by  palpation  alone. 
Percussion  will  also  demand  more  time  and  skill. 
(c)  The  combined  methods  (on  the  same  persons)  will  yield  a 
greater  malaria  index  than  each  method  by  itself — 
often  a  much  greater  one  than  that  given  by  the 
parasite  index  by  itself,  and  a  considerably  greater 
one  than  that  given  by  the  spleen  index.     If,  how- 
ever, Laveran,  Thayer,  Mannaberg  and  others  are 
right  in   their   opinion   that   some   enlargement   of 
the  spleen  can  be  detected  by  percussion  in  almost 
all    infected    persons,   then   the   combined    parasite 
index  and   spleen  index  (by  palpation  alone)   can 
yield   little   more   information   than   that   given  by 
a    careful    spleen    rate   ascertained    by    percussion. 
The  combined  method  will,  however,  require  much 
more    time,   and    will    give    no    exact    information 
regarding  the  non-infected  spleen  ratio. 
Subject  to  correction,  then,   I   conclude  that,  as  a  general 
rule,  the  spleen  index  (obtained   by  palpation  only)  is   by  far 
the  best  method  of  measurement.     It  requires  no  great  skill ; 
it  can  often  be  applied  to  almost  all  the  people  in  a  place  ; 
and  it  should  yield  by  itself  a  very  correct  measure  of  the 
actual    malaria   rate.       As   a    rule,   local    conditions,    race   and 
other  diseases  are  likely  to  cause  a  percentage   of  error   far 
smaller   than   that   due   to   the   insufficient    random    sampling 
which  must  almost  always  attend  the  laborious  estimation  of 
the  parasite  index  (the  advocates  of  which  frequently  overlook 
this  important  point).     But  of  course,  in  the  presence  of  other 
widespread  causes  of  splenomegaly  (kala-azar  or  some  unknown 
cause),  the  spleen  index  by  itself  will  not  be  so  reliable. 

Practically,  therefore,  it  comes  to  this,  that  we  must  avoid 
two  principal  sources  of  error,  (a)  the  possibility  that  the 
local  splenomegaly  may  be  due  to  other  causes  than  malaria, 
and  ih)  the  great  error  of  insufficient  random  sampling.  For 
the  former  purpose  we  must  first  satisfy  ourselves,  by  the  study 


3i]  PRACTICAL   CONCLUSIONS  245 

of  hospital  records  (especially  of  autopsies),  by  consultation 
with  local  physicians,  and  by  the  blood  examination  of  selected 
cases,  that  the  local  splenomegaly  is  really  due  to  malaria.  For 
the  second  purpose,  if  the  first  point  is  established,  we  should 
rely  upon  a  large  spleen  census.  The  time  required  for  a 
laborious  study  of  the  parasite  index  will  generally  be  much 
better  spent  in  extending  the  spleen  census  so  as  to  avoid 
large  error  of  sampling  ;  and  the  combined  method  will  only 
occasionally  be  required  for  some  special  purpose,  such  as 
ascertaining  the  infected  non  -  spleen  ratio,  or  the  infantile 
malaria  index. 

We  must,  of  course,  always  consider  the  season,  the  time 
allotted  for  the  work,  the  amount  of  assistance  available,  and 
the  population  and  area  to  be  examined.  For  large  populations 
the  parasite  index  becomes  almost  impossible.  Not  the  least 
advantage  of  the  spleen  index  is  that  it  can  be  applied  equally 
well  to  a  population  of  any  size. 

B.  TJie  actual  infantile  malaria  rate. — This  is  especially 
valuable  by  (10)  for  determining  the  inoculation  rate.  It  can 
often  be  obtained  among  infants  on  estates  and  factories,  in 
soldiers'  families,  and  in  many  villages.  As,  however,  infants 
up  to  one  or  two  years  of  age  are  not  always  very  numerous 
among  small  populations,  and  the  information  required  is 
important,  it  is  generally  advisable  and  possible  to  use  com- 
bined methods  for  examining  them.  The  ages  should  be 
obtained  as  accurately  as  possible  for  each  month  for  two 
years,  and  the  infants  examined  as  regards  spleen,  parasites, 
fever,  anaemia  and  history  of  illness. 

The  information  obtained  should  be  compared  with  the 
formula  at  the  end  of  (10).  If  we  assume,  as  argued  above, 
that  the  general  spleen  index  practically  coincides  with  the 
general  malaria  rate,  and  denote  the  spleen  ratio  by  S  and 
the  infantile  ratio  by  /,  then  the  formula  becomes 
S^^S-^l{\-S)-rS 


246  MALARIA   IN   THE   COMMUNITY  [Sect. 

If  5^  =  5,  r=i/S  a  month,  and  /  is  a  monthly  infantile  rate, 
then  we  should  have  /=5/5(i-5). 

It  is,  of  course,  best  to  examine,  if  possible,  all  the  infants 
and  to  compare  their  numbers  at  different  ages  with  the 
numbers  given  by,  or  calculated  from,  the  last  census  of  the 
population. 

C.  Comparative  estimates  from  time  to  time  or  place  to 
place. — For  these  we  adopt  the  same  methods  according  to 
the  same  principles.  But  we  can  now  often  utilise  the  valuable 
information  given  by  the  attendances  at  hospitals  and  dispen- 
saries (5).  That  is,  we  obtain  the  ratio  of  attendances  for 
malaria  to  attendances  for  all  causes,  and  compare  them  from 
time  to  time  or  place  to  place. 

Remember  that,  for  comparative  estimates,  ratios  of  indices 
should,  ceteris  paribus,  be  equivalent  to  ratios  of  actual  rates — 
which  makes  the  task  much  easier. 

The  conduct  of  the  malaria  census  will  be  referred  to  in 
connection  with  the  whole  campaign  (section  40). 

32.  The  Mortality  and  Cost  of  Malaria. — A  little  considera- 
tion will  convince  the  reader  of  the  difficulty  of  this  part 
of  the  subject.  The  term  malarial  death-rate  should  mean 
the  percentage  of  persons  who  die  of  malaria.  Such  rates 
can  easily  be  obtained  in  the  case  of  plague,  cholera  and 
other  diseases  in  which  the  cause  of  death  can  be  generally 
assigned  with  certainty  ;  but  malaria  is  a  benign  and  protracted 
disease  which  is  often  complicated  and  terminated  by  other 
maladies,  such  as  pneumonia,  infantile  diarrhoea,  dysentery, 
ankylostomiasis,  and  so  on  ;  and  it  is  often,  perhaps  usually, 
impossible  to  say  whether  death  has  not  been  due  as  much 
to  one  of  these  complications  as  to  the  original  infection. 
Even  with  troops  and  prisoners  the  cause  of  death  in  such 
cases  is  often  ascribed  to  one  or  the  other  cause  on  the 
evidence  of  the  most  predominant  symptoms  at  the  end. 
Even  if  we  admit  the  correctness  of  the  diagnosis  as  regards 


32j  MORTALITY   OF   MALARIA  247 

deaths  in  hospital,  still  the  hospital  case  mortality  is  no  correct 
guide  to  the  total  case  mortality,  because  only  the  more  acute 
cases  among  the  general  population  come  to  hospital  at  all. 
Probably  the  great  majority  of  malaria  deaths  occur  among 
the  children  of  the  poor,  and  in  the  tropics  these  are  seldom 
brought  to  hospital,  or  even  attended  by  medical  men.  The 
fact  that  in  most  tropical  countries  the  cause  of  death  is  not 
necessarily  certified  by  medical  men  adds  still  more  to  our 
difficulties.  Indeed  the  so-called  malaria  death-rates  given  in 
many  statistics  are  not  even  worth  looking  at. 

The  parasites  of  malaria  cause  death  in  two  ways  :  (a)  by 
direct  action,  and  (d)  by  enfeebling  the  constitution. 

Deaths  by  direct  action  probably  occur  only  in  "  pernicious 
attacks."  Celli  (section  20  (6)  )  records  that  330  pernicious 
attacks  occurred  in  33,507  cases  —  about  1%,  and  of  these 
probably  only  a  fraction  were  fatal. 

W.  H.  Deaderick  collects  many  useful  facts  in  his  text- 
book [1909],  and  gives  records  of  case  mortality  amongst  them. 
Out  of  5,109,001  cases  collected  from  twenty-five  writers, 
148,055  or  2-89%  died  (I  judge  that  these  were  mostly  severe 
cases  treated  in  hospital).  Out  of  27,039  cases  of  perm'a'ous 
malaria,  recorded  by  thirty  observers,  7,205,  or  2&6'y^  died. 
Out  of  6,037  cases  of  blackwater  fever  (one  of  the  most 
pernicious  forms),  1,268,  or  21%  died. 

In  India  for  1907  we  have  the  following  figures  (combining 
intermittent  and  remittent  fevers) : — 


Strength. 

Admissions. 

Deaths. 

Malarial 
mortality%. 

Case 

mortality%. 

European  troops  . 

69,332 

10,662 

14 

•020 

•13 

Native  troops 

126,392 

28,432 

84 

•066 

•30 

Prisoners 

93.264 

17,841 

88 

•094 

•51 

The  highest  malarial  mortality  here  given,  that  of  the 
prisoners,  may  be  put  at  about  i/iooo;  but  we  can  see  at 
once  that  this  is  sure  to  be  too  low  an  estimate  for  a  large 
general  population.  Troops  and  prisoners  live  in  cleanly  sur- 
roundings, are  well  housed,  well  fed,   well  treated  in  hospital, 


248  MALARIA   IN   THE   COMMUNITY  [Sect. 

and  (still  more  important)  are  all  adults.  Moreover,  in  my 
experience,  medical  men  rarely  attribute  death  to  malaria 
alone  unless  there  are  no  very  marked  complications.  The 
rate  amongst  a  large,  poor,  general  population,  including 
children,  is  therefore  likely  to  be  several  times  greater.  But 
we  have  no  figures  to  indicate  the  difference. 

As  just  mentioned,  the  deaths  attributed  in  public  statistics 
to  malaria  are  generally  worthless  in  the  tropics,  as  they  are 
not  even  certified  to  by  medical  men.  They  are  often  much 
too  high,  because  the  perplexed  registrar  has  no  other  cause 
to  give  when  dysentery,  cholera,  fits  or  debility  fail  him.  For 
example,  in  Mauritius  the  deaths  attributed  to  malaria  con- 
stituted 14  per  mille,  or  about  half  of  the  total  mortality.  In 
1899,  however,  the  medical  certification  of  deaths  was  enforced 
in  two  districts  of  the  island — with  the  result  that  the  mortality 
ascribed  to  malaria  fell  in  them  at  once  from  45^  of  the  total 
deaths  to  only  25^.  From  this  we  calculate  that  quite  20^  of 
the  general  mortality  was  wrongly  ascribed  to  malaria.  But 
even  with  this  correction  many  sources  of  error  remain. 

Is  there  no  better  criterion  of  the  true  malarial  death-rate.? 
In  most  civilised  countries  to  -  day  the  total  death  -  rate  is 
correctly  reported  :  we  may  therefore  obtain  useful  information 
by  comparing  the  total  mortality  in  various  areas  which  differ 
in  possessing  or  not  possessing  malaria,  but  which  are  alike 
in  other  respects.  Take,  for  example,  Mauritius  (malarious) 
and  the  neighbouring  Seychelles  Islands  (not  malarious). 


n-       •,•       f  Population 
Mauritius  ^  ^  ^  , 

I  Death-rates 

Seychelles]  P^P"';^^^^" 
I  Death-rates 

Difference 

For  the  seven  years  1897  to  1903  the  mean  death-rate  in 
the  Seychelles  was  only  lyi  per  inille  against  347  in  Mauritius. 
If  the  whole  of  this  great  difference  is  to  be  ascribed  to  malaria 


1904 

1905 

1906 

Means 

387,395 

386,128 

383,206 

385,576 

32'2 

40  "6 

40'o 

37-6 

20,418 

20,767 

20,976 

20,720 

i6-i 

15-0 

i6-5 

15-9 

i6-i 

25-6 

23-5 

217 

32]  MORTALITY  249 

alone,  we  must  suppose  that  the  true  malarial  death-rate  in 
Mauritius  may  average  something  like  20  per  mille  per  annum 
or  more  —  that  is,  a  mortality  exceeding  the  total  mortality 
from  all  causes  in  the  Seychelles  and  in  most  British  towns. 

The  figures  are  accurate,  the  deaths  being  carefully  registered 
both  in  the  Seychelles  and  in  Mauritius,  and  the  islands  have  a 
very  similar  climate.  But  in  the  mountainous  Seychelles  there 
are  few  or  no  Anophelines  as  in  Mauritius.  The  population  of 
the  former,  however,  is  of  negro  origin,  and  in  the  latter  of 
Indian  origin  and  much  more  dense. 

The  following  are  some  figures  for  ten  other  neighbouring 
islands  of  the  Indian  Ocean — all  not  malarious.  The  popula- 
tions were  those  of  the  census  taken  in  1901,  and  the  death- 
rates  were  the  averages  for  the  following  five  years.  Rodrigues, 
3,437.  I9'3;  ^i^go  Garcia,  526,  27-0;  Agalega,  327,  31-2;  Peros 
Banhos,  184,  24-0;  Coetivy,  143,  36*4;  Salomon,  119,  32*0;  Six- 
Islands,  117,  29-0;  St  Bratidon,  ?,y,  55*3;  St  Jean  de  Nove,  75, 
i6'0  ;  Eagle  Island,  74,  43-0.  Total  population,  5,134.  Average 
death-rate,  31-5.  Owing  to  the  smallness  of  the  population  in 
the  lesser  islands  the  statistical  error  is  large;  but  the  mortality 
in  some  of  them,  in  spite  of  the  absence  of  malaria,  appears 
to  be  as  great  as  that  of  Mauritius.  There  is,  however,  an 
important  difference.  In  Mauritius,  the  Seychelles  and 
Rodrigues  good  medical  attendance  is  available,  but  this, 
I  understand,  is  not  the  case  in  the  other  islands,  where 
syphilis,  beri-beri,  infantile  tetanus,  bowel  complaints,  ovarian 
and  uterine  diseases  abound,  and  deaths  in  child-birth  are 
common.  Excluding  these  islands,  therefore,  the  difference  as 
regards  the  mortality  between  Mauritius  with  malaria,  and 
Rodrigues  and  the  Seychelles  without  it,  remains  a  striking 
one.  The  large  malarious  island  of  Reunion  (negroid  popula- 
tion) has  a  mortality  similar  to  that  of  Mauritius. 

The  entry  of  malaria  into  Mauritius  in  1866  is  interesting 
in  this  connection  (section  30  (21)).  All  deaths  in  the  island 
have  been  registered  since   1831.     In  the  thirty-six  years  from 


250  MALARIA   IN   THE   COMMUNITY  [Sect. 

183 1  to  1866,  the  average  death-rate  was  35*3  per  mille  in  a 
population  varying  from  93,000  in  1831  to  365,000  in  1866. 
In  the  next  five  years  the  death-rates  were  120*5,  567,  35'0, 
22*6  and  44' i  respectively;  and  in  the  forty  years  from  1867 
to  1906  they  averaged  357 — almost  the  same  as  before  the 
entry  of  malaria.  Thus,  apparently,  while  the  disease  caused 
a  great  increase  of  mortality  for  two  years  after  its  entry,  it 
has  caused  no  increase  whatever  since  then !  In  my  report 
[1908],  however,  I  have  discussed  this  anomaly.  As  Dr 
Meldrum  suggested,  the  extraordinary  low  mortality  of  1870 
was  possibly  due  to  the  death  from  malaria  of  many  persons 
in  1867  and  1868  who  would  otherwise  have  died  in  1870. 
The  high  death-rate  before  the  entry  of  malaria  was  probably 
due  to  many  epidemics  of  measles,  small-pox,  relapsing  fever 
and  cholera,  and  to  the  immaturity  of  medical  and  sanitary 
practice  in  those  days.  Since  the  entry  of  malaria  there  have 
been  few  of  such  epidemics,  and  medical  and  sanitary  practice 
have  greatly  improved,  while  vaccination  has  been  rendered 
compulsory — so  that  the  death-rate  should  have  fallen  to  the 
low  level  found  in  Rodrigues  and  the  Seychelles.  Hence  we 
may  perhaps  assume  that  it  has  not  fallen  because  of  malaria. 
In  other  words,  the  disease  has  counterbalanced  all  the  successes 
of  medical  science  against  other  maladies. 

The  late  Dr  Meldrum,  Director  of  the  Meteorological 
Observatory  in  Mauritius,  and  an  experienced  statistician,  study- 
ing the  monthly  death-rates  from  all  causes  in  Mauritius  before 
and  after  the  entry  of  malaria,  observed  that  they  differed  in 
an  important  particular.  Before  the  malaria  entered  they 
remained  roughly  the  same  from  month  to  month ;  after  it 
entered  the  curve  rose  markedly  during  the  malarious  months. 
In  the  Seychelles  and  Rodrigues  the  monthly  rates  still  remain 
uniform  as  in  Mauritius  before  malaria  entered.  The  following 
table  gives  the  population  and  number  of  deaths. 


S2J 

M( 

aRTALI 

TY 

251 

Average 
population. 

Januar)'. 

February. 

March. 

April. 

May. 

June. 

Seychelles. 

1901-04 

19,442 

31 

28 

27 

30 

26 

33 

Mauritius. 

1861-66 

345,275 

1,003 

936 

987 

920 

972 

898 

1870-89 

353,958 

790 

809 

1,005 

1,043 

1,118 

1,059 

1904-06 

376,974 

1,012 

981 

1,307 

1,314 

1,357 

1,262 

Average 
population. 

July. 

August. 

Sept. 

Oct. 

Nov. 

Dec. 

Seychelles. 

1901-04 

19,442 

30 

23 

26 

27 

26 

25 

Mauritius. 

1861-66 

345,275 

970 

971 

947 

970 

910 

967 

1870-89 

353,958 

1,004 

893 

783 

759 

718 

740 

1904-06 

376,974 

1,597 

1,284 

1,125 

1,089 

1,285 

909 

In  the  first  two  lines  the  monthly  deaths  are  fairly  uniform  ; 
in  the  latter  two  they  are  lowest  in  November  or  December, 
before  the  malaria  season,  and  highest  after  that  season. 
Meldrum  also  enunciated  another  law  based  on  the  careful 
study  of  Mauritian  statistics,  namely,  that  the  highest  death- 
rate  generally  occurs  about  two  months  after  the  heaviest  rain- 
fall. But  the  figures  for  other  countries  show  that  there  may 
be  many  disturbing  factors — heat,  cold  and  epidemics.  Never- 
theless, Meldrum's  laws  should  be  used,  together  with  other 
data,  in  the  study  of  local  malaria  death-rates  [1881,  1890], 
We  should  endeavour  to  ascertain  the  average  ordinary 
mortality,  exclusive  of  epidemics,  during  the  non  -  malarious 
months,  especially  those  just  before  the  commencement  of  the 
increase  probably  due  to  malaria.  The  difference  between  this 
average  and  the  total  mortality  during  what  we  have  reason 
to  suppose  are  the  months  of  malarial  mortality  should  give 
some  rough  indication  of  the  amount  of  the  latter,  S.  R. 
Christophers  has  recently  suggested  [1910]  that  rises  in  the  total 
mortality,  7ninus  other  epidemics,  should  indicate  epidemics  of 
malaria.  They  should  also  indicate  endemic  variations.  But 
of  course  in  all  such  studies  an  accurate  knowledge  of  local 
circumstances — climate,  rainfall,  other  diseases — is  required. 

So  far  as  I  can  see  the  only  method  by  which  we  can  hope 


252  MALARIA   IN  THE   COMMUNITY  [Sect. 

to  ascertain  the  increase  in  the  general  mortality  really  due  to 
malaria  would  be  to  undertake  a  careful  comparison  of  the 
death-rates  and  spleen  rates  over  a  large  area  and  for  a  con- 
siderable period.  The  task  would  be  a  suitable  one  for  all 
Health  Departments,  and  ought  to  have  been  performed  long 
ago  —  if  only  to  determine  that  fundamental  question,  the 
actual  amount  of  mischief  caused  by  the  disease. 

In  1898  I  proposed  to  undertake  such  a  survey  in  Mauritius, 
and  collected  a  number  of  figures  from  the  sugar  estates  [1898]. 
Unfortunately,  the  death-rates  could  not  be  obtained  for  the 
period  during  which  the  spleen  rates  were  taken ;  and  other 
fallacies  invalidated  the  data.  In  section  22,  however,  the  rates 
are  given  for  the  various  districts  of  the  island.  The  healthiest 
district,  Moka,  showed  a  spleen  rate  of  4-4%  and  a  death-rate 
of  only  \%"]  per  milk,  while  Black  River  had  a  spleen  rate  of 
567%  and  a  death-rate  of  39*5%  (on  the  estates).  This  again 
suggests — as  we  saw  from  a  comparison  of  Mauritius  and  the 
Seychelles  —  that  malaria,  when  severe,  may  actually  double 
the  general  mortality.  But  before  accepting  such  an  appalling 
estimate  I  should  like  to  see  the  subject  worked  out  step  by 
step  —  I  should  like  to  know  for  several  countries  and  races 
the  rise  in  the  mortality  step  by  step  for  every  rise  of  10% 
in  the  spleen  rate.  Until  this  is  done  we  remain  merely  in 
the  clouds  of  medical  conjecture. 

What  precisely  is  the  economical  loss  to  the  community  caused 
by  malaria  ? — From  the  preventive  point  of  view  this  is  perhaps 
the  most  important  question  before  us ;  because,  obviously, 
it  governs  the  question  of  the  expenditure  which  may  be 
demanded  for  the  anti-malarial  campaign.  In  order  to  answer 
it  we  must  know  {a)  the  real  malarial  mortality ;  {b)  the 
constantly  sick  rate  (section  31  (6));  and  {c)  the  local  values 
of  human  life  and  labour  at  various  ages  and  in  various  social 
classes.  Considering  the  importance  of  the  theme,  I  had  hoped 
to  give  here  a  detailed  estimate ;  but  I  find  that  the  data  are 
quite  insufficient.     We  do  not  know  even  the  real  death-rate, 


32]  COST  253 

much  less  the  death-rates  at  various  ages ;  and  the  values  of 
life  and  labour  vary  so  much  that  different  estimates  must  be 
prepared  for  each  country. 

Many  such  estimates  have  been  attempted.  I  will  mention 
here  as  an  example  only  one  by  Dr  Bolton,  Medical  Officer 
of  the  Immigration  Department  of  Mauritius  (because  I  have 
already  given  so  many  statistics  of  that  colony).  There  are 
about  39,CX)0  adult  male  coolies  on  the  sugar  estates,  of  whom 
about  15%  are  incapacitated  by  malaria  for  three  months  in 
the  year.  That  is,  more  than  500,000  days'  work  is  lost 
annually.  The  day's  work  is  worth  1/4  rupee  to  coolies  and 
5/4  rupee  to  the  planter  ;  so  that  the  coolies  lose  about  125,000 
rupees  and  the  planters  about  625,000  rupees  per  annum,  or 
750,000  rupees  altogether.  Besides  the  males  there  are  about 
8,000  women  working  on  the  estates,  and,  at  the  same  rate, 
these  lose  108,000  days'  work,  worth  21,000  rupees  at  0"20 
rupees  a  day.  Similarly,  outside  the  estates,  there  are  30,000 
Indian  coolies,  earning  0*5  rupees  a  day ;  and  these  lose  about 
20,250  rupees  a  year.  Thus  the  workers  lose  about  166,250 
xn^ees  per  annum,  and  the  employers  considerably  over  650,000 
rupees.  With  hospital  and  other  expenditure  Dr  Bolton 
estimates  that  malaria  costs  Mauritius,  with  its  population  of 
383,000,  about  1,000,000  rupees  a  year  (a  rupee  is  about  1/15 
pound  English) — that  is,  about  2*6  rupees  per  head.  Enhance- 
ment of  wages,  cost  of  invaliding,  and  loss  of  market  are  not 
considered.  Similarly,  L.  O.  Howard  estimates  that  malaria 
costs  the  United  States  $100,000,000  a  year  (section  41).  See 
also  section  65  (9). 


CHAPTER   VI 

PREVENTION 

33.    List  of  the   Possible   Preventive   Measures.  —  One 

advantage  of  the  malaria  formula  given  in  section  28,  equation 
4,  is  that  it  enables  us  not  only  to  name  the  various  preventive 
measures,  but  also  to  obtain  some  quantitative  estimate  of  their 
relative  utility.  Suppose  that  an  anti-malaria  campaign  is 
contemplated  in  any  locality,  and  let  m  be  the  proportion  of 
infected  persons  at  the  beginning  of  the  campaign,  and  m^  be 
the  proportion  at  the  end  of  a  given  period.  Then  by  the 
formula 

■)n^  —  in  +  U'-saii^  i  —  m)ni  —  rm. 
Hence   m   will  be  less  than  m^,  that   is,  the  malaria  will  be 
reduced,  if  we  can   make  suitable  modifications  in  the  factors 
b,  J,  a,  /,  V.     Such  modifications  can  be  made  in  various  ways, 
as  follows : — 

The  biting  factor,  b,  represents  the  average  proportion  of 
Anophelines  which  succeed  in  biting  individuals.  We  have 
roughly  estimated  it  at  1/4.  Obviously,  if  we  diminish  this 
fraction  we  shall  diminish  the  malaria  in  the  locality.  This 
can  be  done  in  many  ways.  The  use  of  ordinary  mosquito-nets, 
of  wire-gauze  to  the  windows  and  doors  of  houses,  oi  punkas 
and  fans  (which  drive  away  the  insects),  of  culicifuges,  that  is, 
substances  which,  when  applied  to  the  skin,  tend  to  keep  them 
off,  and  even  the  use  of  smoke,  woollen  clothing  and  bed  cover- 
ings, must  all  tend  to  have  the  desired  effect.  But,  of  course, 
if  we  hope  to  reduce   the    malaria   throughout  a  considerable 

254 


Sect.  33]  POSSIBLE   MEASURES  255 

population,  such  measures  must  be  adopted  by  a  sufficiently 
large  number  of  people.  No  appreciable  effect  will  be  pro- 
duced on  the  general  malaria  rate  if  only  a  few  persons  take 
the  trouble  to  use  them,  because  d  expresses  the  average  pro- 
portion of  insects  which  succeed  in  biting. 

The  next  factor  in  the  equation  is  s,  which  denotes  the 
proportion  of  insects  that  succeed  in  maturing  the  parasites, 
and  which  we  have  generally  taken  at  about  1/3.  This  factor 
depends  principally  upon  the  species  factor  of  the  local 
Anophelines  (section  30  (11)).  Certain  species  certainly  suc- 
ceed in  maturing  the  parasites  more  easily  than  others  do,  and, 
moreover,  it  has  been  suggested  that  certain  foods  inhibit  the 
growth  of  the  organisms  in  the  insects,  while  cold  also  does 
the  same  thing.  I  fear  that  we  are  unable  to  modify  this 
factor  by  itself. 

The  next  factor,  a,  denotes  the  number  of  different 
Anophelines  to  each  person,  and  can  be  modified  by  any  of 
the  measures  adopted  for  mosquito  reduction  ;  that  is,  the  adult 
insects  may  be  killed  by  hand,  or  by  various  culicicides,  or 
perhaps  by  the  introduction  of  enemies,  such  as  certain  bats 
or  birds.  Or  the  larvae  may  be  destroyed  in  numbers  of  ways, 
such  as  emptying  out  the  water  containing  them  or  applying 
larvicides  of  various  kinds,  or  introducing  certain  fish  or 
beetles.  Or  the  breeding  of  the  insects  may  be  checked  by 
removing  water  suitable  for  their  larvae  or  the  weeds  in  which 
they  often  flourish.  Or  the  locality  may  be  rendered  unsuitable 
for  a  given  species  of  Anopheline  by  doing  anything  to  modify 
the  conditions  which  that  species  loves,  such  as  removal  of 
forest  or  undergrowth.  Lastly,  reduction  of  the  biting  factor,  b, 
may  tend  to  reduce  the  total  mosquito  density,  according  to 
section  29  (7). 

The  factor  i  denotes  the  average  proportion  of  infected 
persons  whose  blood  contains  the  sexual  forms.  This  can  be 
modified  to  a  certain  extent  by  the  careful  treatment  of  the 
patients — though    we   must   remember   that   quinine   does  not 


256  PREVENTION  [Sect. 

have  much  influence  on  the  crescents  when  these  are  once 
produced  (sections  23  and  65). 

The  factor  r  denotes  the  average  proportion  of  infected 
persons  who  recover  during  a  given  period,  and  this  can 
certainly  be  very  largely  modified  by  suitable  treatment  of  the 
sick.  It  is  true  that  certain  authors  declare  that  quinine  does 
not  have  much  effect  on  relapses  (section  23),  but  in  the  opinion 
of  a  majority  of  observers  early  and  continued  medication 
certainly  produces  marked  results.  Such  treatment  of  persons 
who  have  had  declared  symptoms  of  the  disease  should  be 
called  case  reduction ;  but  we  should  observe  that  a  similar 
treatment  may  be  commenced  in  persons  before  they  have  had 
any  symptoms  at  all.  That  is  to  say,  all  persons  in  a  locality 
may  take  quinine  continuously  on  the  chance  that  they  may 
have  happened  to  have  become  infected  without  their  know- 
ledge, and  in  the  hope  of  checking  the  parasitic  invasion  at  its 
very  outset.  This  method  of  dealing  with  the  disease  should 
be  called  quinine  prophylaxis.  For  case  reduction  we  treat  the 
sick,  for  quinine  prophylaxis  the  healthy. 

It  will  therefore  be  observed  that  we  have  many  preventive 
measures  against  malaria ;  but  the  ones  given  do  not  close 
the  list.  Another  important  measure  is  that  of  segregation. 
Instead  of  destroying  the  local  mosquitos  or  their  breeding- 
places  we  may  segregate  ourselves  or  a  number  of  people  from 
their  haunts ;  and,  obviously,  this  will  have  the  same  effect 
upon  the  segregated  people.  Or  we  may  segregate  ourselves 
or  a  number  of  people  from  the  infected  area  by  removal  to 
any  locality  where  the  original  malaria  ratio  in  is  less. 

The  reader  will  now  do  well  to  suppose  various  values  for 
the  factors  in  the  equation  and  then  to  calculate  that  of  m^  on 
these  suppositions.  Suppose,  for  instance,  that  the  malaria 
ratio  has  been  remaining  at  the  static  limit  of  one-half,  so  that 
by  section  28,  equation  4,  the  number  of  Anophelines,  a,  should 
be  about  T]  to  each  person.  Now  suppose  that  a  is  reduced  to 
one-half:  then  m^  falls  from   1/2  to  9/20.     Next,  suppose  that 


34]  BED-NETS  257 

b  is  reduced  to  one-half:  then  m^  falls  to  17/40 — a  slightly  lower 
figure,  because  the  factor  b  in  the  equation  is  squared.  Lastly, 
suppose  that  r  is  increased  by  proper  treatment  to  twice  the 
previous  recovery  rate  of  1/5  :  then  m^  becomes  4/10 — which  is 
still  lower.  But  if  we  increase  the  recovery  rate  we  are  likely 
also  to  decrease  the  proportion  of  persons  with  gametids  in 
their  blood,  /.  Suppose  that  if  the  first  is  doubled  the  latter 
will  be  halved  :  then  m^  falls  from  1/2  to  7/20.  Lastly,  suppose 
that  several  of  the  factors  are  changed  simultaneously  —  for 
example,  reduce  a  and  i  to  1/2  and  double  r:  then  m^  falls  to 
13/40.^  This  subject  will  be  discussed  again  in  section  39,  but 
the  reader  should  familiarise  himself  at  once  with  the  ideas 
involved  in  order  to  understand  the  following  matter. 

Many  of  the  measures  were  first  named  and  discussed  in  my 
little  book  called  "  Instructions  for  the  Prevention  of  Malaria 
Fever,"  and  my  series  of  articles  in  the  British  Medical  Journal, 
both  published  anonymously  in  the  autumn  of  1899.  The 
principles  then  laid  down  by  me  have  since  then  been  repeated 
in  many  papers  and  text-books.  We  now  proceed  to  examine 
them  in  detail. 

34.  Protection  against  the  Bites  of  Mosquitos.— (i)  Port- 
able bed -nets. — The  bed -net  was  well  known  to  the  ancients 
under  the  name  oi conopeum  (section  i).     It  is  now  used  almost 
everywhere  in  the  tropics  by  those  who  can  afford  it,  and  adds 
greatly   to   the  comfort  of  life,  apart  from  the  prevention    of 
malaria.      Long   before   the   connection   between   malaria   and 
mosquitos  became  known.  General  Outram  of  Indian  fame,  and 
Emin    Pasha   of    African    fame,    and    others,   attributed  their 
immunity  from  the  disease  to  their  care  in  the  use  of  the  net. 
In  fact,  when  I  went  to  India  in  1881,  it  was  a  common  saying 
amongst  sportsmen,  planters  and  many  residents  in  that  country, 
that  the  way  to  keep  off  malaria  was  to  use  a  net  under  all 
circumstances. 

^  Or  we  can  use  the  static  formula,  section  28,  equation  7. 


258  PREVENTION  [Sect. 

But  the  net  must  be  used  properly,  and  the  following  rules 
carefully  attended  to:  — 

(a)  Not  a  single  rent  or  hole  in  the  net  must  be  allowed. 
If  there  is  one,  mosquitos,  which  spend  the  whole 
night  in  exploring  every  inch  of  the  net  in  the  hope 
of  reaching  the  sleeper,  are  sure  to  find  it  and  enter. 
Not  only  should  there  be  no  rent  or  hole,  but  the 
net  should  be  so  hung  that   no  aperture  for  entry 
is  left.     Thus  it  should  always  be  hung  inside  the 
poles  provided  for  the  purpose,  and  tucked  continu- 
ously all  round  under  the  mattress.     It  should  not  be 
hung  outside  the  poles,  because  then  it  cannot  be 
tucked  in  satisfactorily  in  the  manner  mentioned  ; 
and  it  should  not  be  allowed  to  hang  down  to  the 
floor  unless  heavily  weighted,  because  then  it  is  apt 
to  be  blown  up  by  the  wind,  thus  allowing  insects 
to  enter.     Moreover,  if  it  is  hung  down  to  the  floor, 
insects  which  are  hiding  under  the  bed  during  the 
daytime  will  often  be  included.     The  servant  should 
be  instructed  to  let  down  the  net  before  dark  in  the 
evening,  and  to  see  that  no  mosquitos  are  inside. 
If  mosquitos  do  find  entry,  it  is  always  due  merely 
to  carelessness. 
(d)  Do  not  have  any  opening  for  the  purpose  of  entering 
the  net.     Such  openings  are  often  used  in  Europe 
and  allow  the  insects  to  go  to  bed  with  the  sleeper. 
When  entering,  one  should  lift  the  lower  edge  of  the 
net  from  the  mattress  as  little  as  possible  and  slip 
in  with  a  twisting  movement,  so  as  to  exclude  stray 
mosquitos   which   may   have   been   hovering  round 
outside.     If  possible,  use  a  large  bed  and  a  large  net 
in  order  to  avoid  the  hands,  knees  and  elbows  being 
pushed  against  the  gauze  during  sleep,  and  thus  being 
bitten  through  the  net  by  mosquitos  outside.       If 
no  large  bed  and  net  are  available,  this  contingency 


34J  BED-NETS  259 

should  be  guarded  against  by  sewing  a  loose  valance 
of  gauze  round  the  lower  part  of  the  net,  about 
9  inches  (23  cm.)  above  the  upper  surface  of  the 
bed,  the  valance  being  tucked  under  the  mattress 
together  with  the  net. 

(c)  The  thread  of  the  netting  should  not  be  too  thick,  as 
if  it  is  so  it  will  exclude  air.  The  mesh  should  be 
neither  too  small  nor  too  large,  the  general  size  fixed 
being  about  eighteen  threads  to  the  inch  (seven  to 
the  cm.).  No  part  of  the  net  should  be  made  of 
any  closer  texture,  as  this  is  quite  unnecessary  and 
excludes  the  air.  For  example,  where,  as  in  India, 
punkas  swing  over  the  bed  all  night,  a  top  of 
calico  merely  excludes  the  breeze  and  adds  to  the 
discomfort  of  the  sleeper.  Of  course,  where  sand- 
flies i^Siinulidae)  are  present,  the  whole  net  must  be 
made  of  closer  texture,  such  as  muslin  or  cambric. 
These  insects  inflict  worse  tortures  than  mosquitos 
do,  and  have  also  been  proved  to  carry  a  particular 
kind  of  fever.  The  netting  should  always  be  white 
to  permit  the  easy  detection  of  insects. 

{d)  In  the  great  heat  of  the  tropics,  the  manner  in  which 
the  net  is  hung  is  very  important.  If  it  is  arranged 
in  thick  or  loose  folds  it  will  exclude  the  cooling 
breeze.  The  net  should  always  be  stretched  as  tight 
as  possible  in  every  direction,  in  order  to  allow  the 
air  to  pass  freely  through  it.  In  fact,  those  who 
complain  that  they  cannot  sleep  under  a  net  because 
it  stifles  them  nearly  always  neglect  this  precaution. 
A  tightly-stretched  net  with  a  thin  thread  excludes 
very  little  breeze.  For  this  reason  the  pattern  of  net 
is  important.  In  my  opinion  much  the  best  nets  are 
the  square  ones  which  are  used  almost  throughout 
India,  and  which  are  capable  of  being  stretched  in 
the  manner  described.     Nets  which  are  bunched  up 


26o  PREVENTION  [Sect. 

at  the  top  and  hung  from  a  single  rope  are  much 
more  close  and  uncomfortable  for  the  sleeper ;  but 
there  is  a  good   pattern  which   contains  a  circular 
hoop  a  yard  or  two  above  the  bed,  permitting  the 
necessary  tight  stretching. 
(e)  Many  patent  patterns  are  advertised,  and  nearly  all  of 
them  are  good  ones.     Different  patterns  are  required 
for  fixed  domiciles  and  for  travelling.     The  traveller 
needs  a  portable  pattern  which  can  be  set  up  very 
quickly  in   any   locality  where   he   may  require  to 
sleep.      Bedsteads  with  attached    nets  are  also  on 
the  market,  and   can  generally  be  obtained  locally. 
Special   patterns  have  been  suggested   for   soldiers 
and  others  who  have  to  bivouac  in   the   open    air. 
I  generally  carry  a  small  square  netting  which  can 
be   hung  inside  the  berths  on  board  ship,  because 
shipowners  are  still  barbarous  enough  not  to  exclude 
mosquitos  by  wire-gauze  at  the  ports  (section  46). 
(2).  Portable  mosquito-proof  rooms. — These  are  simply  large 
nets,  generally  square  and  capable  of  holding  the  entire  bed, 
together  with  a  small  table  and  chair,  and  perhaps  a  rotatory 
fan.      Several  special  patterns  are  on  the  market.      They  are 
very  useful  for  travellers.     Entirely  mosquito-proof  tents  have 
also  been  advertised,  and  should  certainly  be  always  used  in 
warm  climates.     The  one  difficulty  about  such  structures  con- 
sists in  the  arrangements  for  entering ;  but  in  my  opinion  it  is 
not  advisable  to  provide  a  special  door  for  doing  so,  as  one 
can  always  creep  in  under  the  lower  edge  of  the  net. 

(3).  Fixed  mosquito-proof  rooms. — These  are  found  in  several 
colonies,  and  consist  of  a  wire  -  gauze  chamber  supported  by 
wooden  uprights  fixed  in  the  floor.  The  mode  of  entry  is 
by  means  of  a  self-closing  door.  The  wire-gauze  is  in  one 
respect  preferable  to  the  cotton  netting,  as  it  allows  more  breeze 
to  enter,  but  on  the  other  hand  mosquitos  which  have  entered 
cannot  be  so  easily  detected  against  the  darker  thread  of  the 


34]  SCREENING  261 

wire.  Of  course,  such  chambers  are  constructed  within  the 
ordinary  rooms  of  a  house,  or  in  the  veranda.  I  have  long 
advocated  the  use  of  them,  during  very  hot  weather,  either  in 
the  open  or  on  the  roof  of  the  house. 

(4).  Mosquito  proofing  of  windows  and  doors. — This  has 
been  long  in  use  in  the  Southern  States  of  America,  and  has 
been  much  advocated  by  French  and  ItaHan  writers  on  malaria. 
The  net  may  be  of  cotton,  but  this,  of  course,  soon  rots  away, 
so  that  wire-gauze  is  always  better.  I  am  very  strongly  in 
favour  of  this  method  of  protection,  which  I  have  seen  in  use 
in  Lagos,  Panama  and  elsewhere.  It  adds  greatly  to  the 
comfort  of  life  in  the  tropics.  It  excludes  not  only  mosquitos, 
but  flies,  moths  and  other  insects,  bats  and  birds.  It  also 
excludes  the  glare  of  the  sun  during  the  day,  and  the  damp 
exhalation  rising  after  heavy  tropical  showers.  At  the  same 
time  it  allows  the  breeze  to  enter  almost  unimpeded. 

The  mesh  of  the  net  should  be  the  same  as  that  used  for 
bed-nets.  The  wire  may  be  either  of  "  tinned  iron "  or  of 
copper  or  brass.  Roughly  speaking,  the  price  of  the  former  is 
about  twopence  a  square  foot  and  of  the  latter  about  three- 
pence a  square  foot  in  British  colonies.  Some  years  ago  a 
number  of  tests  were  carried  out  by  the  Crown  Agents  for  the 
Colonies  on  behalf  of  the  British  Colonial  Office,  showing  that 
tinned  iron  soon  rots  away  in  consequence  of  damp.  But  I 
once  saw  in  Lagos  a  greenhouse  covered  in  entirely  with  tinned 
iron  wire-gauze  which  had  remained  quite  sound  for  more  than 
five  years,  even  in  that  warm  damp  climate.^ 

The  question  how  the  gauze  should  best  be  applied  to 
the  windows  has  been  much  discussed,  especially  by  Laveran 
[1907],  who  gives  many  diagrams  and  pictures.  As  a  matter 
of  fact,  the  question  has  generally  to  be  decided  according  to 
the  form  of  the  windows  already  existing  in  a  house.  The 
problem  is  an  easy  one  with  sliding  sashes.  In  such  cases  I 
advocate  that  the  wire-gauze  be  permanently  nailed,  with  nails 

^  See  also  sections  46  and  55. 


262  PREVENTION  [Sect. 

of  the  same  metal  (in  order  to  prevent  galvanic  rust),  outside 
the   window ;  that   is,   if  the   shutters   are   hung   inside.      For 
French  windows,  which  open  outwards  on  hinges,  the  problem 
is  much  more  difficult,  because  if  the  wire-gauze  is  fixed  inside, 
the  windows  cannot  be  opened.     Many  types  are  adopted  in  such 
cases,   but   they  are   not   always   satisfactory.     Movable  wire- 
gauze  frames  which  require  trouble  to  put  up  are  sure  to  be 
neglected  by  servants.     In  my  opinion  it  is  best  in  such  cases 
to  refit  the  windows  so  that  they  can  be  made  to  open  inwards, 
and  then  to  fix  the  wire-gauze  outside,  or  vice  versa.     Further 
details  are  better   left   to   the   intelligence  of  the  reader.     In 
climates  which  are  never   cold,  the   glass  of  the  windows  can 
be  replaced  entirely  by  wire-gauze,  thus  simplifying  the  problem. 
Doors   afford   another   problem.      The    Italians   have   long 
advocated    double    swing    doors    with    a   protected    entry,   but 
this    is  necessary  only  where  the   insects   abound   very    much. 
Automatic  swing  doors  generally  suffice.     Of  course,  in  order 
to  protect  a  room  or  a  house  completely,  every  possible  orifice, 
including   key-holes,   chimneys   and    chinks    round    doors   and 
windows  should  be  properly  closed  or  guarded  ;  but  the  details 
are  so  numerous  that  it  is  useless  to  give  them  in  writing. 

Wurtz  [1907]  states  that  a  solution  of  commercial  silicate 
of  potassium  in  its  own  volume  of  water,  if  painted  several 
times  with  a  brush,  without  drying  between  the  coats,  upon  a 
piece  of  ordinary  cotton  netting  stretched  on  a  window-frame 
or  elsewhere,  will  make  the  netting  much  stronger  and  more 
resistent  to  water  or  fire.  The  painting  can  be  done  in  five 
minutes.  The  solution  dries  in  an  hour.  The  mesh  should 
be  large,  as  the  interstices  are  partially  filled  by  the  solution. 
In  this  manner  cotton  netting  can  be  utilised  for  window  and 
house  protection.  The  suggestion  is  a  very  good  one  and 
might  be  developed  further. 

(5).  Mosquito  proofing  of  verandas. — This  adds  largely  to  the 
expense  of  protecting  houses,  but  is,  of  course,  a  very  great 
addition    to    comfort.      A    large    part    of    the    Meteorological 


34]  CULICIFUGES  263 

Observatory  in  Mauritius  was  proofed  in  this  manner  at  the 
cost  of  several  thousand  rupees,  and  the  measure  is  much 
adopted  in  Panama  and  elsewhere.  A  much  less  costly 
procedure  is  to  protect  a  single  corner  of  the  veranda.  This 
was  insisted  upon  by  Sir  William  MacGregor  in  Lagos,  and  is 
now  adopted  in  that  colony.  Something  of  the  kind  should 
always  be  used,  as  people  must  have  somewhere  to  sit  in 
during  the  evening. 

(6).  ProteMon  for  the  hands  and  feet. — In  1898  many  writers 
advocated  protection  of  this  nature.  It  was  suggested  that 
whole  armies  should  go  on  the  march  with  veils  over  their 
faces  and  thick  woollen  gloves  —  a  rather  difficult  suggestion 
for  the  tropics.  The  Italians  have  dealt  with  this  matter  at 
considerable  length,  and  Laveran  quotes  and  figures  the  pro- 
tection given  to  Japanese  soldiers  in  Formosa  and  Manchuria. 
Special  boots  to  protect  the  ankles  have  also  been  recommended. 
Personally,  I  think  that  such  means  of  protection  are  too 
uncomfortable  for  general  use,  and  I  much  prefer  a  hand  fan 
(mentioned  presently). 

(7).  Medicinal  protectives. — Many  attempts  have  been  made 
to  find  protective  applications  to  the  skin.  Oil  of  lavender,  of 
eucalyptus,  petroleum,  ammonia,  powdered  sandal-wood,  and 
many  patent  fluids  have  been  recommended  to  me  for  the  purpose, 
but  when  I  have  recommended  them  to  others,  I  have  not 
always  received  favourable  reports  regarding  them.  Laveran 
[1907]  mentions  numerous  statements  on  the  subject  regard- 
ing sulphur,  petroleum,  a  mixture  of  tar  and  oil,  and  quassia. 
Vaseline  (100  parts),  naphthaline  (10  parts),  camphor  (i  part) 
has  been  recommended  ;  but  he  adds  that  his  own  experiences 
were  unfavourable  with  such  substances.  Fermi  and  Lumbau 
[1900]  tested  many  substances  without  marked  success.  Celli 
[1901]  states  that  the  old  custom  of  hanging  bags  containing 
garlic  or  camphor  round  the  neck  originated  in  their  protective 
effect  against  mosquitos. 

We   should   observe   that   experiments  on  the  point   must 


264  PREVENTION  [Sect. 

be  very  exact  to  be  convincing ;  that  the  effect  of  volatile 
substances  is  sure  to  be  transient  ;  and  that  the  use,  even 
of  successful  protectives,  can  only  be  exceptional,  as  when 
mosquitos  are  very  numerous,  because  few  people  will  ever 
be  persuaded  to  smear  themselves  constantly  with  them,  and 
because  they  would  probably  affect  the  skin  after  a  time. 
Such  protectives  do  not  come  at  present  within  the  domain 
of  practical  sanitation. 

(8).  Constant  movement. — As  a  general  rule  (but  not  always), 
mosquitos  bite  only  when  their  victim  remains  quiet.  Hence 
I  have  formed  the  habit,  when  in  danger  of  being  bitten,  of 
maintaining  constant  small  movements  of  the  hands,  feet  and 
head.  I  find  this,  together  with  the  use  of  a  hand  fan,  far 
preferable  to  the  employment  of  hot  gloves,  thick  clothing  or 
inunctions. 

(9).  Fans  and  punkas. — A  palm  leaf  can  be  purchased  almost 
anywhere  in  the  tropics  for  a  penny,  and  serves  not  only  to 
drive  away  mosquitos,  but  also  to  keep  the  body  cool. 

Fans  rotated  by  electricity  or  small  hot  air  engines  are  now 
frequently  used  in  the  tropics  by  those  who  can  afford  them. 

Punkas  consist  of  a  board  or  canvas  stretched  upon  a 
wooden  framework,  hung  by  one  edge  from  the  roof,  and 
swung  backwards  and  forwards  by  means  of  a  rope  or  pulley 
worked  by  hand  labour  or  (in  barracks  and  hospitals)  by 
machines.  The  constant  movement  and  the  current  of  air 
prevent  mosquitos  biting  even  a  sleeping  person.  Probably 
the  alternating  movement  has  a  better  effect  for  this  purpose 
than  the  uniform  movement  of  a  rotatory  fan.  The  punka 
should  not  consist  merely  of  a  pole  with  a  fringe  of  cloth 
hung  from  it,  because  the  yielding  fringe  gives  no  current 
of  air. 

(10).  So7ue  results. — Perhaps  the  first  example  of  the  utility 
of  ordinary  bed-nets  was  cited  by  myself  [22nd  July  1899].  In 
October  1898  a  company  of  the  "Boys'  Brigade"  of  Calcutta 
went  to  live  for  one  week  in  a  house  in  Barrackpur  Park,  near 


35]  RESULTS   OF   PROTECTION  265 

the  River  Hoogly.  The  three  officers  and  a  friend  slept  in 
bed-nets,  but  thirteen  boys  did  not.  The  officers  and  their 
friend  remained  well ;  but  all  the  boys,  together  with  a  sister 
of  one  of  them,  were  attacked  a  few  days  later.  The  first  boy 
attacked,  died.  Mosquitos  were  very  numerous.  Three  native 
servants  (without  nets)  also  suffered. 

In  1899  also  many  experiments  were  made  on  the  Italian 
railways  by  screening  stations  and  houses  of  employees.  The 
results  were  summed  up  as  follows  by  Celli  [1902].  Out  of 
4,363  completely  protected  persons,  r9^  became  infected  and 
2i'i%  had  relapses.  Out  of  5,165  incompletely  infected  persons 
3*3^  became  infected  and  20^  had  relapses.  Out  of  802  persons 
protected  only  during  sleep  iO'9^  became  infected.  The  local 
fever  index  was  40-60^,  or  even  more. 

Laveran  [1907]  quotes  an  experiment  among  Japanese 
troops  in  Formosa,  of  whom,  out  of  646  unprotected  men, 
there  were  285  cases  of  malaria,  and  out  of  115  protected 
men  there  were  none ;  and  also  cites  several  similar  small 
experiments  in  Corsica,  Algeria,  Holland  and  Senegal.  In 
nearly  all  of  these  cases,  however,  quinine  as  well  as  protective 
screening  was  used.  The  experiment  of  Sambon  and  Low 
(section  7)  served  a  useful  purpose  at  the  time  in  advertising 
the  mosquito  theory,  but  there  was  no  very  strong  scientific 
evidence  that  the  subjects  would  have  been  infected  during  the 
experimental  period,  even  without  the  protection. 

Further  experiments  should  be  performed  in  order  to  ascer- 
tain the  effect  of  mechanical  protective  measures  alone. 

35.  Mosquito-reduetion. — This  can  be  effected  {a)  by  direct 
destruction  of  mosquitos  or  their  larvae,  and  {b)  by  rendering 
houses  or  localities  less  suitable  for  them  or  for  the  breeding 
of  them. 

(i).  Destruction  of  adults  by  hand.  —  Large  numbers  of 
mosquitos  can  be  destroyed  in  houses  by  a  very  simple  device 
— a  small  hand-net.     This    is   made  for  a  shilling  or  two  by 


366  PREVENTION  [Sect. 

tying  a  piece  of  flexible  cane  or  other  wood  or  wire  in  the 
form  of  a  loop,  to  which  a  bag  of  white  netting  about  i8  inches 
deep  (4"5  decimetres)  is  attached.  The  net  must  be  white  and 
not  green,  in  order  to  enable  us  to  see  the  captured  insect 
through  the  mesh.  Any  one  can  easily  secure  his  persecutors 
by  means  of  it,  and  thus  obtain  respite  for  some  time. 

Sir  William  MacGregor  employed  a  boy  to  kill  mosquitos  in 
this  manner  in  his  house  in  Lagos  in  1901.  In  lofty  rooms  a 
long-handled  net  may  be  required  to  catch  the  insects  under 
the  roof. 

Colonel  Gorgas  and  Mr  Le  Prince  advocate  (sections  42 
and  43)  the  employment  of  men  for  this  purpose  and  give 
examples.  I  think  that  every  householder  should  possess  such 
a  net  and  should  instruct  his  servants  to  use  it  regularly.  The 
same  thing  should  be  done  in  hospitals,  barracks,  military  camps 
and  jails. 

Much  more  could  be  accomplished  by  this  simple  method 
than  has  yet  been  attempted.  Boys  become  very  expert 
at  catching  mosquitos.  The  offer  of  rewards  of  a  penny 
for  fifty  Anophelines  may  quite  possibly  lead  to  a  large 
slaughter  by  village  children.  Probably,  for  unit  of  cost 
and  trouble,  more  mosquitos  can  be  killed  by  hand  than  by 
fumigation. 

(2).  Fumigation.  —  This  method  has  long  been  employed, 
especially  in  Italy  and  the  United  States.  The  discovery  of 
the  carriage  of  yellow  fever  by  Stegomyia  calopus  gave  great 
stimulus  to  it  for  sanitary  purposes.  In  yellow  fever  it  is 
absolutely  necessary  that  every  Stegomyia  which  has  bitten 
the  patient  should  be  killed  for  fear  lest  it  may  infect  other 
persons  ;  and  this  is  rendered  easier  because  the  yellow  fever 
patient  remains  infective  only  for  three  days,  and  because 
vS.  calopus  is  a  domestic  insect.  But  destruction  of  adults  is 
not  so  useful  for  the  prevention  of  malaria,  because  patients 
continue  to  be  infective  at  irregular  periods  for  a  long  time, 
and  because  the  carriers  are  often  wild  insects  (section  29  (4)) 


35]  DESTRUCTION   OF    MOSQUITOS  267 

which  may  remain  only  an  hour  or  two  in  houses.  Hence 
the  expensive  and  troublesome  process  of  fumigation  is  not 
much  employed  in  malaria  prophylaxis. 

Celli  and  Casagrandi  made  experiments  with  many  sub- 
stances [Celli,  1901].  Thick  tobacco  smoke  and  chloroform 
appear  to  be  the  best,  and  have  been  known  for  a  long  time. 
Sulphur  dioxyde,  hydrogen  sulphide,  coal  gas,  formaldehyde,  kill 
in  one  to  two  minutes  (but,  curiously  enough,  acetylene  gas  seems 
to  be  quite  innocuous).  Fumes  of  pyrethrum  powder  causes 
apparent  death  in  five  minutes  and  actual  death  in  eight  hours. 
Numerous  agents  for  the  destruction  of  insects  in  greenhouses 
are  on  sale  and  are  equally  effective  against  mosquitos. 

Boyce  [1909]  describes  very  thoroughly,  and  with  good 
illustrations,  the  methods  of  fumigation  practised  against 
yellow  fever  in  America.  His  recommendations  have  already 
been  given  (section  12). 

In  India  fumigation  is  seldom  used :  and  it  would  be 
difficult  to  apply  in  the  thatched  mud  huts  or  leaf  shelters 
of  the  poor.  But  I  think  that  destruction  by  hand  could  be 
employed  more  than  it  is. 

Mosquito-traps  were  also  described  in  sections  12  and  60. 
Wells,  cellars,  privies,  stables  and  dark  rooms  are  natural 
traps  in  which  the  insects  often  congregate  in  large  numbers 
and  can  easily  be  destroyed. 

(3).  Introduction  of  7iatural  enemies. — Bats,  birds,  lizards, 
dragon  flies  and  other  flies  are  known  to  catch  mosquitos ; 
but  whether  their  presence  makes  any  marked  effect  on  the 
number  of  the  insects  is  another  question,  which,  so  far  as 
I  know,  has  not  been  studied. 

It  has  been  known  for  a  long  time  that  small  fish  devour 
the  larvae  ;  and  indeed  the  larvae  were  used  for  feeding  the 
fry  of  British  trout  introduced  into  India,  in  my  memory, 
before  1890.  Fish,  however,  vary  greatly  in  their  liking  for 
the  larvae.  Thus  in  Mauritius  the  small  gold  fish  which  abound 
in  ornamental  waters  eat  them,  but  not  voraciously.     On  the 


268  PREVENTION  [Sect. 

other  hand,  I  saw  in  India  in  1890- 1899  minnows  which  would 
devour  a  dozen  or  more  in  a  few  seconds  and  would  visibly 
swell  after  the  meal.  The  waters  of  Panama  contain  a 
minute  fish,  less  than  an  inch  long,  which  is  equally  fond  of 
them,  and  which  thrives  in  quickly  running  streamlets.  The 
same  is  true  of  the  common  small  fish  at  Ismailia.  On  the 
other  hand,  large  fish  often  disdain  such  small  prey.  I  saw 
a  ditch  in  Calcutta  full  of  small  fish  and  also  absolutely  thick 
with  mosquito  larvae  ;  and  have  observed  fish  and  larvae 
living  together  in  rice  fields. 

Boyce  [1909]  well  describes  the  larvicidal  propensities  of 
Girardinus  poeciloides,  popularly  called  "  millions,"  a  minute 
fish  probably  allied  to  the  one  which  abounds  at  Panama. 
Mr  C.  Kendrick  Gibbons  in  1905  attributed  to  it  the  immunity 
of  Barbados  from  malaria.  The  people  keep  these  fish  even 
in  water  receptacles,  of  which  Boyce  examined  sixty  without 
finding  larvae.  The  Imperial  Department  of  Agriculture  in 
Barbados  has  introduced  millions  into  Jamaica,  St  Kitts  and 
Antigua.  Further  references  to  larvae-eating  fish  will  be  found 
in  Chapter  VII  I.i 

Tadpoles,  Notonecta  (the  water  boatman),  and  the  larvae 
of  several  insects  eat  mosquito  larvae  ;  and  indeed  the  latter 
are  often  cannibals. 

This  part  of  the  subject  is  of  great  importance  and  is 
now  receiving  considerable  attention.  Obviously,  the  success 
of  the  measure  must  depend  largely  upon  the  habits  of  the 
local  malaria  carriers — whether  they  breed  mostly  in  perma- 
nent pools  where  fish  and  their  other  enemies  also  can  live,  or 
whether  they  abound  elsewhere,  as  in  evanescent  rain-water 
pools.  The  question  depends  entirely  upon  the  local  con- 
ditions and  requires  local  study. 

No    cheaper    and    better    anti-malaria    measure    than    the 

^  J.  Chaytor-White  suggests  the  importation  of  "millions"  into  India  [1910]. 
He  reproaches  me  for  not  recommending  the  measure  for  Mauritius.  This  was  due 
to  oversight,  and  the  fish  are  being  introduced. 


35]  ENEMIES   OF   MOSQUITOS  269 

extermination  of  Anophelines  by  natural  enemies  could  be 
conceived  or  devised — were  such  a  thing  possible.  It  may  be 
possible  in  some  places  ;  while  for  other  places  we  may  not 
be  able  to  find  the  suitable  enemy.  Unfortunately,  experience 
proves  that  animals  and  plants  often  survive,  even  in  large 
numbers,  the  introduction  of  their  most  deadly  enemies  ;  they 
succeed  in  finding  some  refuge  or  other,  and  a  state  of  com- 
mensalism  is  finally  arrived  at.  For  example,  Anophelines 
abound  in  the  Panama  Canal  Zone  in  spite  of  the  fish  referred 
to.  It  is  only  the  academical  hygienist  who  believes  that 
any  measure  which  suggests  itself  is  sure  to  be  practically 
useful.  It  may  often  happen,  too,  that  the  expense  of  main- 
taining the  "  enemy "  will  be  greater  than  that  of  removing 
the  breeding  water  entirely.  Nevertheless,  we  should  seek 
what  allies  we  can  find.^ 

It  has  often  been  observed  that  parts  of  India  where 
M.  rossii,  which  seem  not  to  carry  plasmodia,  abounds  are 
comparatively  free  from  malaria.  Quite  possibly  it  may 
tend  to  crowd  out  other  species,  thus  reducing  them  below 
the  malaria-bearing  limit,  although  it  does  not  exterminate 
them  entirely.  Experiments  on  this  point  are  much  required, 
and  I  have  suggested  them  tentatively  for  Mauritius.  The 
comparative  freedom  of  large  tracts  where  the  conditions 
appear  to  be  favourable  must  be  due  to  some  cause.  If  we 
can  ascertain  the  factor  we  may  be  able  to  introduce  it  else- 
where (section  30  (10)  and  (u)). 

H.  Marcus  Fernando,  in  a  suggestive  paper  just  to  hand 
[1910],  points  out  that  though  Colombo,  Ceylon,  is  surrounded 
by  low-lying  grass  fields,  subject  to  periodic  inundations,  it 
is  practically  immune  from  malaria.  This  he  attributes  to 
swarms  of  minnows  and  other  enemies  of  mosquitos.  He 
states  also  that  very  hot  dry  seasons  are  often  followed  by 
much  malaria,  simply  because  they  tend  to  destroy  the 
aquatic  enemies  of  the  larvae.     These   views    accord   exactly 

^  See  also  section  54. 


270  PREVENTION  [Sect. 

with   those  already  expressed  in  section   30  (i),  (6)  and  (10). 
So  also  rice  fields  are  often  not  malarious — as  in  Madras  town. 

(4).  Destruction  of  larvae — The  methods  employed  depend 
on  where  the  larvae  are  found. 

For  small  movable  receptacles  of  water,  such  as  broken 
bottles  and  crockery,  empty  tins,  flower  -  pots,  gourds,  old 
buckets  and  tubs,  fire-buckets,  fallen  palm  leaves,  etc.,  emptying 
out  suffices  for  the  moment.  But  such  articles  ought  to  be 
collected  in  suitable  dust-bins,  and  the  laws  regarding  the 
proper  deposition  of  rubbish  ought  to  be  strictly  enforced. 

Oiling. — This  method,  long  known,^  was  first  elaborated  as 
a  public  health  measure  in  my  reports  on  Sierra  Leone  [1899]. 
It  is  employed  wherever  the  previous  methods  are  inapplicable, 
or  where  the  water  is  required  for  use,  or  where  more  permanent 
measures  cannot  be  adopted  at  the  time — that  is,  for  water 
butts,  metal  cisterns  of  drinking  water,  wells,  garden  cisterns, 
washing  waters,  cesspits  and  so  on.  The  method  has  now 
become  familiar  to  all.  The  oil  is  poured  on  the  water  and 
broken  up  so  that  it  quickly  forms  a  thin  film  all  over  the 
surface.  The  larvae  and  pupae  are  no  longer  able  to  keep 
the  surface  by  surface-tension  and  quickly  drown  —  Laveran 
thinks  that  the  oil  chokes  the  breathing  tube  [1907]. 

The  oil  may  be  poured  on  the  water  out  of  a  tin  or  kettle, 
or  by  means  of  a  special  syringe.  For  small  pools,  I  advocated 
that  each  man  engaged  on  the  work  should  be  provided  with  a 
tin  of  oil,  and  a  bunch  of  rag  tied  to  the  end  of  a  stick.  The 
rag  is  dipped  in  the  oil,  which  is  now  "  painted,"  on  the  surface 
of  the  pool — but  such  details  are  unimportant. 

It  is  best  to  use  the  cheapest  oils  in  the  local  market. 
Refined  petroleum  spreads  rapidly  and  well,  but  evaporates 
quickly.  Crude  petroleum  is  cheaper  and  makes  a  much 
more  lasting  film.  For  Ismailia  I  recommended  an  equal 
mixture  of  the  two.  Celli  [1901]  said  that  0"i  c.cm.  was  the 
minimum  amount  required  per  square  metre  of  surface,  but  Fermi 

^  Howard  [1893]  and  Nuttall[  1 899]. 


35]  POOLS   AND    HOLES  271 

and  Lumbau  [1900]  require  5*0  c.cm.,  and  others  various  amounts. 
Experiments  in  vitro  are  of  little  use ;  and  the  amount  required 
depends  on  the  quality  of  the  oil,  the  heat  of  the  sun,  the  amount 
of  vegetation,  dSris,  etc.,  and  should  be  determined  locally. 
Logan  Taylor  and  I  found  crude  creosote  to  be  very  useful  in 
Sierra  Leone ;  it  is  more  deadly,  but  also  much  more  expensive 
than  crude  petroleum.  For  killing  larvae  in  drinking  waters, 
Strachan  recommended  me  to  use  eucalyptus  or  juniper  oil. 

For  pools  it  is  advisable,  and  indeed  sometimes  necessary, 
to  remove  vegetation  before  applying  the  oil. 

My  brother,  E.  H.  Ross,  described  an  automatic  oiler  for 
cess-pits  at  Port  Said,  and  Gorgas  and  Le  Prince  mention 
"  cotton  waste "  soaked  in  oil. 

Celli  and  Casagrandi  [Celli  1901]  and  others  describe 
experiments  with  many  substances.  Aniline  dyes  are  active 
destroyers.  Gallol  and  Green  Malachite  kill  to  a  certainty  in 
solutions  of  0'Oi25/iooo  and  O'25/iooo,  and  a  mixture  called 
"  larvicide "  appears  to  be  very  effective.  They  diffuse  them- 
selves continuously  in  water,  are  not  volatile,  and  do  not  poison 
men,  cattle,  or  crops.  Celli  says  that  larvicide  costs  from  12  to 
56  lire  for  destroying  larvae  in  10,000  cubic  metres  of  water. 
It  is  said  to  have  little  action  on  the  pupae. 

Oiling  should  also  be  used  for  the  tins  of  water  placed  under 
the  feet  of  tables  and  meat-safes  in  order  to  exclude  ants  ;  and 
for  saucers  under  water  bottles,  flower-pots  and  filters. 

Small  pools  of  water  on  the  ground,  especially  those  which 
form  after  heavy  showers,  or  in  rocks  along  the  margin  of 
streams,  or  in  gutters,  open  drains,  and  stone  water-channels, 
can  often  be  quickly  brushed  out,  water,  larvae,  and  all,  by 
means  of  a  broom. 

Holes  m  rocks  and  trees  are  best  dealt  with  simply  by 
filling  up  with  earth  or  gravel  as  a  temporary  measure,  or 
with  concrete  as  a  permanent  one. 

Plants  which  breed  mosquitos  should  be  removed  if  possible. 
In    Mauritius,   Bilbergia   splendida^   a   wild    pine-apple   with   a 


272  PREVENTION  [Sect. 

gorgeous  flower,  was  planted  in  most  of  the  gardens  and  kept 
the  houses  supplied  with  innumerable  Scutomyia  notoscripta 
Skuse,  until  the  wiser  inhabitants  rooted  them  up  during  and 
after  my  visit.  Cut  bamboo  stems  should  be  cut  again  flush 
with  the  next  knot,  or  with  the  ground.  Unfortunately, 
mosquitos  often  breed  in  palm  trees  and  sugar  cane  —  in 
which  case  I  can  recommend  nothing  but  grease  being  applied 
at  the  off-shoot  of  the  leaves.  The  householder  has  often  to 
determine  whether  he  will  sacrifice  his  plants  to  his  comfort. 
It  is  mostly  the  Qilicines  which  breed  in  such  situations. 

Rain-water  gutters  along  the  eaves  of  houses  are  best  dealt 
with  by  boring  a  small  hole  in  the  most  dependent  part  of  the 
gutter  where  the  water  stagnates.  Heavy  old  metal  cisterns, 
etc,  not  worth  removal,  can  often  be  treated  in  the  same  manner, 
(5).  The  screening  of  breeding  waters, — We  now  proceed  to 
consider  methods  for  rendering  localities  or  houses  less  suitable 
for  mosquitos  or  for  their  breeding.  We  will  deal  first  with 
what  I  call  "  minor  works." 

Mosquitos,  more  especially  the  Culicines,  breed  very  much 
in  collections  of  water,  such  as  water  -  butts,  cisterns,  wells, 
cess  -  pits,  etc.,  which  cannot  be  dispensed  with,  and  which 
should  be  so  protected  that  the  insects  cannot  lay  their  eggs 
in  them.  At  the  same  time  it  is  often  necessary  to  ventilate 
the  water.  For  this  purpose  we  should  apply  covers  which 
are  so  scrupulously  well  fitted  that  no  insect  can  enter,  and 
at  the  same  time  protect  the  ventilating  orifice  by  wire-gauze. 
In  many  countries  tubs  are  used  outside  houses  to  collect 
rain-water  from  the  roof,  A  wooden  top  should  be  closely 
fitted  and  a  hole  of  about  6  inches  or  more  in  diameter 
should  be  cut  in  it.  Nail  down  a  piece  of  wire-gauze  on  the 
outside  of  the  orifice.  The  pipe  which  brings  the  water  from 
the  roof  discharges  over  the  orifice,  so  that  the  water  flows 
directly  into  the  barrel,  being  drawn  out  by  a  tap  below. 
Similar  devices  can  be  employed  for  cisterns,  but  if  these  are 
made   of   metal   and   have   badly   fitting   covers,   considerable 


35]  WELLS  AND   CESS-PITS  273 

difficulty  is  often  experienced  in  making  the  proper  arrange- 
ments, which  must  be  left  to  the  reader. 

The  subject  of  wells  is  of  great  importance  in  the  tropics, 
as  they  are  often  the  only  source  of  drinking  water.  For  the 
usual  hygienic  reasons  the  people  should  never  be  allowed  to 
lower  buckets  and  ropes  into  wells,  as  this  frequently  leads 
to  serious  defilement  of  the  water.  In  my  opinion  every  well 
should  be  furnished  with  a  closely  fitting  cover,  the  water 
being  drawn  by  means  of  a  pump  of  some  kind.  But  in 
order  to  ventilate  the  water,  a  hole  protected  by  strong  wire- 
gauze  should  be  cut  in  the  cover.  I  have  seen  excellent  wells 
of  this  kind  in  several  localities,  notably  at  Bathurst,  Gambia. 

Cess-pits  are  frequently  used,  especially  in  French  possessions, 
and  are  ventilated  by  long  pipes  which  discharge  at  the  roofs 
of  the  houses.  We  observed  at  Ismailia  that  Culicines  were 
breeding  in  large  numbers  in  these  pits,  though  they  were 
entirely  closed  except  for  the  ventilating  shafts,  down  which 
adults  found  entrance  and  exit.  To  prevent  this  it  is  necessary 
only  to  protect  the  ventilation  with  strong  wire -gauze.  In 
badly-made  cess-pits  there  are  other  orifices  by  which  the 
insects  can  enter.  These  should  be  done  away  with  as  much 
as  possible.  If  they  cannot  be  completely  filled  up,  the  pits 
must  be  regularly  oiled  by  some  method  (section  53). 

(6).  Dealing  with  breeding-holes. —  I  have  already  mentioned 
that  holes  in  trees  and  rocks  should  be  filled  with  concrete, 
that  is,  with  a  mixture  of  Portland  cement  and  sand  or  gravel. 
The  best  mixture  for  the  locality  should  be  determined  by 
local  engineers.  Two  men  must  work  together,  one  carrying 
concrete  and  the  other  laying  it  into  the  holes.  Mosquito 
breeding-holes  in  trees  are  sometimes  very  difficult  to  find, 
men  or  boys  having  to  climb  the  trees  for  the  purpose.  Hence, 
when  they  are  found  their  position  should  be  marked  on  the 
tree  by  a  conspicuous  patch  of  paint  for  future  identification. 
Inexperienced  persons  are  apt  to  think  that  such  work  is 
altogether  too  much  for  human  weakness  to  accomplish,  but 

s 


274  PREVENTION  [Sect. 

as  a  couple  of  men  can  generally  fill  fifty  holes  a  day,  it  is 
not  long  before  most  of  the  breeding  -  places  round  houses 
are  disposed  of.  In  many  cases,  moreover,  the  water  in  such 
holes  can  easily  be  liberated  by  cutting.  If  concrete  is  not 
available,  earth,  gravel,  or  stones  often  suffice  perfectly  for  a 
considerable  period.  A  little  trouble  guided  by  common  sense 
is  all  that  is  required. 

Garden  cisterns  often  occasion  much  difficulty.  Water  is 
required  for  irrigating  plants,  and  is  often  allowed  to  stagnate 
for  weeks  in  the  cisterns.  The  best  way  to  deal  with  them 
is  to  direct  that  not  too  many  of  these  cisterns  be  allowed  to 
remain,  so  that  those  which  are  permitted  to  do  so  shall  be 
in  constant  use.  The  frequent  agitation  of  the  water  by  the 
gardener  generally  suffices  to  check  mosquito-breeding  in  it. 
The  gardener  should  be  instructed  to  deal  with  his  irrigation 
water  in  such  a  manner  as  not  to  cause  breeding  of  mosquitos. 
Here,  again,  details  can  be  better  left  to  the  reader. 

Irrigation  pits  are  often  employed  for  cultivation,  and  are 
found  to  contain  Anophelines,  which  live  especially  in  the 
presence  of  grass  and  vegetation  occurring  at  the  edge  of 
the  water.  These  are  often  difficult  to  deal  with,  as  the 
people  occasionally  require  the  water.  If  possible,  they  should 
be  filled  in,  but  if  this  is  not  possible,  we  can  often  render  them 
unsuitable  for  larvae  by  dragging  out  the  weeds  and  "  backing 
up"  the  margin  of  the  pit  by  filling  with  large  stones,  the 
owners  being  instructed  to  prevent  the  new  growth  of  vegetation, 
A  gang  of  men  will  deal  in  this  manner  with  a  number  of 
such  pits  in  a  day. 

Borrow  pits,  that  is,  pits  from  which  earth  has  been  taken 
for  building  purposes,  are  found  everywhere,  and  are  not 
always  easy  to  deal  with.  They  may  often  be  filled  up 
with  ordinary  town  rubbish,  but  this  should  be  ultimately 
packed  into  them  closely  and  covered  with  a  layer  of  earth. 
In  some  places  they  can  be  filled  up  at  greater  expense  with 
stones  brought  from  a  distance,  if  such  are  available.     Where 


35]  BORROW-PITS  275 

they  cannot  be  filled  up,  the  best  plan  to  deal  with  them  is 
by  the  method  just  suggested  for  irrigation  pits.  Where  no 
stones  can  be  obtained,  and  where  the  water  cannot  be  drained 
away,  our  only  resource  is  to  deepen  the  bed.  Make  the  banks 
"  steep-to  "  all  round,  and  clear  away  all  the  vegetation,  leaving 
the  water  as  before.  Such  places  are  particularly  suitable  for 
the  introduction  of  natural  enemies  of  larvae  ;  but  they  must 
be  examined  from  time  to  time  to  see  whether  they  are  really 
free  from  mosquitos. 

A  number  of  small  questions  of  this  nature  are  apt  to 
rise  in  connection  with  cultivation,  and  must  be  left  to  the 
ingenuity  of  the  director  of  the  works.  Railway  companies 
often  cause  much  trouble  by  their  borrow  pits  along  the  course 
of  railways,  and  they  continue  to  do  so  in  spite  of  the  protests 
of  medical  men.  This  is  a  point  which  should  always  be  taken 
note  of  by  the  Government  of  the  colony,  who  should  insist 
upon  the  borrow  pits  being  so  made  as  to  allow  the  water  to 
run  off.  I  know  that  in  absolutely  flat  country  this  is  difficult, 
if  not  impossible ;  but  in  such  cases  much  can  be  done  by 
making  regular  pits  without  marshy  borders,  and  by  insisting 
that  these  shall  be  kept  free  of  vegetation,  and  shall  be  stocked 
with  fish,  etc. 

Built  conduits  and  drains. — By  this  I  mean  water-courses 
and  drains  which  run  through  masonry.  In  the  course  of  time 
the  masonry  is  apt  to  wear  away,  thus  leaving  breeding-holes. 
These  holes  can  be  dealt  with  by  rebuilding,  or  by  filling  with 
concrete. 

(7).  Training  the  banks  of  streams,  rivers  and  lakes. — The 
word  "  training "  is  one  used  by  engineers  to  signify  rendering 
banks  more  regular  or  solid.  Untrained  streams  and  lakes 
are  apt  to  spread  over  the  ground  beyond  their  margins,  and 
to  cause  innumerable  small  breeding-pools,  and  the  object  of 
the  training  is  to  check  this  tendency.  The  director  of  the 
work  must  be  guided  by  circumstances  how  this  can  best  be 
done.     In  many  places  the  water  may  be  deepened,  the  earth 


276  PREVENTION  [Sect. 

taken  from  the  bottom  being  used  to  build  up  a  steep  bank. 
In  other  places  large  stones  may  be  arranged  along  the  margins. 
Everywhere  the  streams  should  be  so  dealt  with  as  to  allow 
the  water  to  run  freely,  and  above  all,  weeds  should  be  dragged 
out  of  the  water,  while  the  banks  are  rendered  as  "  clean  "  and 
permanent  as  possible.  The  Forest  Department  in  Mauritius 
"  canalised  "  a  stream  in  this  way,  at  the  cost  of  only  0*37  rupees 
a  running  foot  for  both  banks.^  While  the  rough  training  is 
in  progress,  holes  in  neighbouring  rocks  may  be  filled  in  with 
cement.  Cattle  often  cause  much  trouble  by  leaving  holes 
in  muddy  banks  in  which  Anophelines  breed  with  readiness. 
This  problem  is  attacked  in  Panama  by  a  rule  that  cattle  be 
allowed  to  water  only  at  fixed  spots  which  are  properly  pre- 
pared by  cobble-stones  to  prevent  such  breeding. 

Exactly  similar  measures  are  required  for  rivers  and  lakes, 
but  the  works  involved  for  them  must  often  be  taken  under 
the  heading  of  major  works.  Irrigation  canals  and  irrigation 
works  in  general  must  be  attended  to  on  the  same  principles. 

It  is  often  stated  that  irrigation  is  not  compatible  with 
mosquito  reduction.  This  is  quite  untrue,  because  in  Ismailia 
at  the  present  day  we  have  an  example  of  the  opposite. 
Ismailia,  though  built  in  the  desert,  is  now  a  well-watered 
garden  without  mosquitos.  Nothing  but  attention  to  the  small 
details  which  I  have  mentioned  is  required,  and  the  expense 
of  the  work  is  very  small.  Idleness  always  finds  an  excuse. 
Small  marshes  can  frequently  be  dealt  with  quite  easily  by 
these  simple  means,  that  is,  merely  by  clearing  the  natural  lines 
of  drainage.  Our  mosquito  gangs  in  Mauritius,  consisting 
merely  of  Indian  workmen,  made  short  work  of  considerable 
areas  of  marsh  in  this  manner.  Only  common  sense  is  required ; 
but,  of  course,  in  other  instances  major  works  by  drainage  have 
to  be  performed  in  order  to  give  a  final  outlet  to  the  water. 

Temporary  marshes  (section  30  (i))  can  be  attacked  on  the 
same  principles. 

*  See  pp.  166  and  450. 


35]  MARSHES  277 

(8).  Major  works. — I  divide  all  works  for  the  reduction  of 
mosquitos  into  two  classes,  namely  {a)  such  as  we  have 
hitherto  dealt  with,  which  can  be  performed  by  any  intelligent 
persons,  and  should  be  called  minor  works  ;  and  {b)  those 
which  require  the  advice  of  an  engineer,  and  which  should 
be  called  major  zvorks.  Naturally,  major  works  generally 
require  a  greater  expenditure  of  capital  than  minor  works, 
though  this  does  not  imply  that  they  are  always  more  ex- 
pensive in  the  long  run.  As  a  general  rule,  I  think,  major 
works  need  not  be  undertaken  until  minor  works  have  failed, 
unless  expert  advice  to  the  contrary  is  given. 

Marshes  are  of  two  kinds,  those  in  which  the  natural  outlets 
for  the  water  are  sufficient  but  have  become  choked  by  vegeta- 
tion, cultivation,  or  other  small  obstructions,  which  can  usually 
be  removed  by  minor  works ;  and  those  in  which  the  natural 
outlets  are  insufficient  and  require  deepening.  For  adequate 
dealing  with  the  latter,  levels  must  be  taken  and  extensive 
works,  directed  by  an  engineer,  are  generally  demanded. 

Marshes  may  be  caused  not  only  by  insufficient  outlet, 
but  by  excessive  inlet.  The  water  in  a  marsh  may  not  come 
merely  from  rainfall  over  the  marshy  area,  but  from  streams 
or  drainage  from  beyond.  Thus  marshes  are  very  apt  to 
occur  at  the  base  of  hills,  small  or  large,  the  rainfall  upon 
which  runs  out  and  stagnates  on  the  plain.  We  must  there- 
fore consider  whether  we  should  increase  the  outlet  or  decrease 
the  inlet ;  whether  we  should  cut  channels  across  a  marsh  in 
order  to  free  the  water  in  it,  or  carry  intercepting  trenches 
round  it  in  order  to  remove  the  incoming  waters. 

In  many  cases,  especially  in  marshes  due  to  periodical 
inundations  by  streams  and  lakes,  the  problem  of  how  best 
to  deal  with  them  can  be  solved  only  by  an  expert.  The 
marsh  may  be  («)  drained  away,  {b)  filled  up,  or  {c)  converted 
into  an  open  lake  too  deep  to  breed  mosquitos.  Estimates 
must  be  prepared,  and  the  engineers  have  to  select  the  best  plan. 

Marshes  difficult  to  deal  with  are  often  formed  by  roads, 


278  PREVENTION  [Sect. 

railways,  houses,  irrigation  canals,  ill-managed  water  conduits 
and  standpipes,  and  even  by  badly-made  drains. 

The  form  of  drain  to  be  employed  often  requires  careful 
thought.  Drains  may  be  (a)  open  channels  cut  in  the  soil  ; 
(d)  open  channels  flanked  with  stone  or  concrete ;  (c)  channels 
filled  with  large  stones  at  bottom  and  gravel  above  (rubble 
drains) ;  or  (d)  various  kinds  of  subsoil  piping. 

All  major  works  require  to  be  constantly  kept  in  repair 
by  minor  works,  that  is,  after  the  major  work  is  done,  there 
must  be  a  constant  expenditure  for  what  engineers  call 
"  maintenance." 

Though  it  may  be  quite  possible  to  treat  a  given  breeding 
surface  by  minor  works  only,  yet  the  expense  of  this  may 
be  so  great  that  it  will  exceed  the  interest  on  the  money 
laid  out  for  clearing  the  area  by  a  major  work  plus  the 
expense  of  maintenance. 

In  all  these  matters  the  advice  of  the  local  engineers  should 
be  sought.  But  this  does  not  mean  that  the  advice  of  the 
director  of  the  anti-malarial  campaign  should  be  disregarded. 
They  must  work  together.  For  instance,  M.  Watson  notes 
(section  57),  that  open  channels  are  quite  effective  in  the 
lowlands  of  his  district,  because  the  local  carrier  will  not 
breed  in  them  ;  but  piped  drains  are  required  in  the  uplands 
where  the  carriers  breed  in  any  open  water-course.^  Obviously 
the  habits  of  the  local  carriers  should  always  be  carefully  ascer- 
tained and  considered,  because  this  is  likely  to  diminish  largely 
the  cost  of  their  reduction. 

Engineering  works  made  in  ignorance  or  in  defiance  of 
this  knowledge  may  do  more  harm  than  good.  For  example, 
I  think  that  most  of  the  malaria  in  Freetown,  Sierra  Leone, 
was  due  to  the  badly-made  drains ;  and  I  have  seen  much 
malaria  caused  by  other  works  constructed  without  regard  to 
their  possible  evil  sanitary  consequences. 

A  whole  book  could  be  written  on  drainage  of  the  soil  as  a 

^  Compare  sections  42  and  43. 


35]  VEGETATION  279 

preventive  of  malaria — the  history  of  the  subject  alone  would 
fill  many  pages.  The  reader  will  find  further  details  in 
the  next  chapter. 

(9).  Trees.  —  Vegetation  has  long  been  known  to  affect 
malaria.  In  some  places  it  seems  to  have  a  bad  effect,  and  in 
others  a  good  effect.  Probably  this  depends  largely  upon  the 
habits  of  the  local  carrier.  We  quite  understand  that  certain 
mosquitos  prefer  wooded  country,  while  others  like  the  open. 
Thus  M.  Watson  finds  that  in  his  district  one  of  the  most 
important  measures  consists  simply  in  clearing  the  jungle 
to  a  considerable  distance  round  habitations.  On  the  other 
hand,  it  has  been  sometimes  claimed  that  trees  round  habita- 
tions exclude  mosquitos  breeding  in  marshes  beyond. 

Suggestions  were  made  some  time  ago  that  eucalyptus  trees 
would  have  the  effect  of  drying  up  the  soil,  and  that  their  odour 
is  inimical  to  mosquitos.  Consequently  many  plantations  of 
eucalyptus  were  made  in  Italy,  Mauritius,  India  and  elsewhere, 
but  the  results  have  been  quite  indefinite,  as  might  be  supposed. 
I  certainly  think  that  eucalyptus  tends  to  dry  up  the  soil,  but 
whether  it  does  so  sufficiently  to  check  mosquito-breeding  is 
another  matter.  The  cost  of  making  plantations  will  generally 
exceed  that  of  minor  works. 

It  is  well  known  that  trees  exhale  a  great  amount  of  damp, 
which  is  always  favourable  to  mosquitos  and  unfavourable  to 
men.  On  the  whole,  then,  I  am  strongly  of  opinion  that  many 
trees  should  not  be  allowed  in  the  proximity  of  houses  or  in 
the  middle  of  towns  in  the  tropics.  In  addition  to  giving  out 
moisture  they  exclude  the  breeze  and  increase  the  heat,  because 
the  amount  of  shade  thrown  by  them  scarcely  compensates 
for  the  cooling  effect  of  wind.  In  the  case  of  houses  surrounded 
by  considerable  grounds,  trees  are  pleasant  and  beneficial  at  a 
distance  from  the  house.  As  already  mentioned,  moreover, 
trees  are  almost  sure  to  breed  Culicines  in  holes  in  their  trunks 
and  principal  branches,  I  therefore  think  that  every  tropical 
country   should    possess    strict    rules    empowering   the   health 


28o  PREVENTION  [Sect. 

department  to  control  the  growth  of  trees  within,  say,  lOO 
metres  of  houses.  In  Port  Louis,  Mauritius,  the  Mayor,  Dr 
Laurent,  very  wisely  made  a  great  reduction  in  the  forestation. 
In  the  same  place  much  discussion  has  occurred  regarding 
what  are  called  the  "  river  reserves."  By  an  old  law  the  forest 
department  insists  upon  maintaining  a  belt  of  trees  in  the 
neighbourhood  of  each  of  the  streams  for  the  purpose,  partly 
of  preserving  the  streams,  and  partly  of  maintaining  the  rainfall, 
forests  being  found  to  increase  the  number  of  rainy  days,  a 
thing  which  is  very  useful  for  various  kinds  of  cultivation.  On 
consideration  I  was  very  doubtful  as  to  the  effect  of  such  river 
reserves,  but  suggested  that  in  the  neighbourhood  of  towns 
and  villages  they  should  be  kept  scrupulously  free  from 
undergrowth. 

As  a  general  rule  undergrowth  is  favourable  to  subdomestic 
and  wild  species  of  Anophelines,  which,  after  leaving  houses 
where  they  find  their  food,  like  to  take  refuge  in  thick  vegeta- 
tion. Personally,  I  prefer  houses  surrounded  by  open  lawns 
rather  than  by  thick  shrubberies.  In  a  house  occupied  by 
Major  Fowler  and  myself  in  Mauritius,  and  surrounded  by 
trees,  the  Scutomyia  notoscripta  was  a  pest  by  day,  while  C. 
fatigans  was  equally  troublesome  by  night.  In  the  barracks 
of  the  European  troops,  however,  situated  in  an  open  grassy 
maidan  a  few  hundred  yards  away,  these  insects  were  not 
nearly  so  numerous.  Many  similar  experiences  might  be 
cited. 

(lo.)  Houses. — Without  making  any  general  attack  on  the 
numbers  of  mosquitos  in  a  locality,  they  can  be  reduced  in 
dwellings  simply  by  the  manner  in  which  the  house  is  built. 
As  a  general  rule  Anophelines  much  prefer  dark  damp  houses, 
especially  with  wooden  or  mud  walls  and  thatched  roofs,  and 
surrounded  by  thick  vegetation.  Lofty  houses  built  of  stone, 
with  large  windows  and  plenty  of  ventilation,  are  not  so 
haunted  by  Anophelines,  though  they  may  sometimes  be  full 
of  Culicines. 


36]  HOUSES  281 

I  am  sure  that  the  colour  of  the  walls  is  a  very  important 
detail.  No  mosquitos  seem  to  like  white  walls  and  ceiling, 
especially  if  there  is  plenty  of  light  (Nuttall  [1901]). 

Europeans  called  upon  to  live  in  the  tropics  are  very  apt  to 
bring  with  them  their  ideas  of  house  decoration,  and  English 
ladies  especially  like  to  furnish  their  drawing  -  rooms  with 
numbers  of  beautiful  curtains,  pictures  and  stuffed  chairs,  all 
of  which  harbour  the  insects.  This  method  of  decoration  is 
rather  barbarous  at  the  best,  and  is  quite  inappropriate  for 
warm  climates.  Curtains  especially  check  the  breeze  which  is 
so  cooling  to  the  inmates  and  so  unpleasant  for  mosquitos. 

The  whole  subject  of  houses  in  the  tropics  requires  very 
careful  consideration.  The  housing  of  the  poor  is  often  simply 
disgraceful.  The  building  laws,  if  any,  are  generally  evaded, 
with  the  result  that  the  mass  of  the  people  have  to  live  in 
the  most  miserable  shanties  made  of  wood,  palm  leaves,  and 
often  of  old  kerosene  oil  tins.  In  every  malarious  country  a 
committee  should  be  appointed  to  consider  the  whole  of  this 
housing  question^  especially  with  a  view  to  excluding  mosquitos 
and  malaria.  Good  houses  suitable  for  the  poor  could  easily 
be  designed,  and  building  laws  could  be  made  in  order  to 
enforce  their  construction  by  degrees.  The  same  remarks 
apply  to  tropical  cities,  where  the  native  quarters  are  generally 
in  a  dreadful  condition.  There  is  no  reason  which  I  can  see 
why  houses  in  the  tropics  should  not  be  as  well  built  as  those 
in  temperate  climates.  This,  however,  is  a  question  of  scientific 
administration  in  opposition  to  those  forms  of  administration 
which  we  meet  with  too  often  in  the  world. 

36.  Prevention  by  Treatment. — It  used  to  be  said  that 
prevention  is  better  than  cure,  but  we  are  now  finding  that 
cure  is  one  of  the  best  methods  of  prevention.  In  all  parasitic 
diseases,  one  way  to  remedy  the  disease  is  to  destroy  the 
parasites  in  the  patients,  who  then  cease  to  spread  them  to 
other   persons.       This   has   been    undoubtedly   the   case   with 


282  PREVENTION  [Sect. 

ankylostomiasis,  and  will  prove  to  be  the  case  with  other 
parasitic  diseases. 

The  history  of  prevention  by  treatment  in  malaria  is  a  long 
one  :  Laveran  [1907]  gives  many  interesting  details.  After 
the  mosquito  theory  was  established,  Koch  was  the  first  to 
call  marked  attention  to  this  method.  He  suggested  that  all 
patients,  especially  children,  should  be  carefully  treated  with 
quinine.  His  principles  were  immediately  tried  in  Italy  and 
in  various  German  possessions  (sections  49,  51);  and  in  Pro- 
fessor Celli's  contribution  to  this  book,  an  admirable  account 
will  be  found  of  the  use  of  the  method  with  more  recent 
extensions  given  by  the  Italians  themselves.  Equally  good 
results  are  quoted  by  other  contributors  to  Chapter  VII,  where 
many  practical  details  are  given. 

As  stated  in  section  33,  treatment  affects  the  malaria 
equation  partly  by  increasing  the  recovery  factor  r,  and  also 
by  reducing  the  proportion  of  infected  persons  with  gametids 
in  their  blood  i.  It  thus  modifies  two  of  the  factors.  Treat- 
ment of  the  sick  only  should  be  called  case  reduction ;  and 
treatment  of  those  who  have  not  yet  shown  symptoms,  but 
who  may  have  become  infected  unknown  to  themselves,  should 
be  called  quinine  prophylaxis. 

We  should  always  understand  that  quinine  does  not  really 
prevent  infection.  I  presume  that  the  protospores  may  be 
inoculated  into  a  person  whether  he  is  taking  quinine  or  not, 
but  that  they  will  not  thrive  in  the  former  case — see  negative 
cases  5  and  6  in  section  1 5.^  We  should  also  understand  from 
section  23  that  quinine,  whether  used  for  case  reduction  or  for 
prophylaxis,  should  be  continued  for  a  long  time. 

The  drug  does  not  have  a  very  lethal  effect  on  the  gametids, 
at  least  those  of  the  malignant  parasites,  when  these  are  once 
formed ;  but  it  certainly  tends  toward  destroying  the  other 
forms.  The  Italians  insist  that  it  does  not  have  much  effect 
upon   relapses,  but,  for  reasons  given  in  section   23,  I  doubt 

^  And  section  65  (5). 


36]  PREVENTION    BY   TREATMENT  283 

whether  they  are  right  on  the  point,  and  am  inch'ned  to  think 
that  the  inadequacy  of  the  treatment  has  been  to  blame  for 
the  recurrences  of  fever.  This  point  is  made  clearer  by  some 
of  our  cases  recently  studied  in  Liverpool  by  enumerative 
methods.  On  the  whole,  there  is  no  doubt  whatever  that  a 
continuous  and  sufficient  use  of  quinine  will  tend  largely  to 
reduce  the  malaria  ratio. 

Another  point  must  not  be  forgotten.  For  public  health 
work  cases  cannot  be  treated  with  the  elaboration  of  detail 
employed  in  hospital  practice.  All  we  can  do  is  to  recommend 
a  general  line  of  treatment  for  the  public  ;  and,  in  fact,  the 
people  must  become  their  own  physicians.  It  is  idle,  therefore, 
under  these  circumstances,  to  suggest  complicated  scales  of 
dosage  and  the  use  of  various  preparations. 

I  have  always  taught,  in  entire  agreement  with  Professor 
Celli,^  that  daily  dosage  is  much  the  best  for  public  health  work. 
He  insists  strongly  that  physiological  immunity  of  the  patients 
against  the  drug  is  much  more  quickly  arrived  at  by  daily 
dosage  than  by  intermittent  dosage — and  I  have  always  found 
the  same.  But  there  is  a  still  stronger  reason  for  daily  dosage. 
If  we  order  quinine  every  few  days,  the  patient  is  apt  to  put 
off  the  evil  hour  until  to-morrow — he  complains  that  he  has 
much  work  to  do  to-day,  or  that  he  has  indigestion,  or  is  not 
feeling  very  well.  When  to-morrow  comes  other  excuses  may 
be  found.  Then  the  patient  is  attacked  with  fever  and  finally 
decides  that  the  quinine  treatment  is  of  no  use.  Personally, 
I  recommend  that  quinine  should  be  given  invariably  once  a 
day,  either  just  before  the  morning  meal  or  at  bedtime. 

With  regard  to  dosage,  I  do  not  advise  quantities  which 
will  disgust  the  people  with  the  drug.  It  is  perhaps  better  to 
use  amounts  which  will  prevent  the  disease  only  in  a  percentage 
of  people,  than  to  cure  all  of  them  at  the  expense  of  making 
them  all  ill.  CelH  recommends  40  centigrams  of  the  bisulphate, 
hydrochlorate,  or  bihydrochlorate  for  adults  and  young  persons  ; 
^  See  section  49,  p.  417. 


284  PREVENTION  [Sect. 

20  centigrams  of  the  same  salts  or  30  centigrams  of  the  tannate 
for  children  ;  and  in  every  case  administered  in  the  agreeable 
form  of  comfits  or  of  chocolates.  But  he  increases  the  dose  to 
50  or  60  centigrams  for  adults  in  the  presence  of  very  severe 
malaria.  I  have  generally  recommended  5  grains  (33  centi- 
grams) for  adults,  and  much  similar  doses  for  children.  It  has, 
of  course,  been  shown  that  children  can  take  quinine  in  larger 
doses  than  adults ;  but,  on  the  other  hand,  I  doubt  whether 
such  larger  doses  are  really  necessary  for  them,  and  the  vomit- 
ing which  is  frequently  caused  in  young  children  by  the  larger 
doses  is  apt  to  alarm  mothers.  In  fact  we  have  to  take  the 
greatest  care  not  to  impose  too  great  a  burden  on  the  people 
whom  we  wish  to  persuade  into  anti-malarial  courses. 

In  India  quinine  is  generally  administered  for  public  use  in 
the  form  of  powders  wrapped  in  papers.  I  think  that  this  is 
a  bad  method,  partly  because  the  taste  is  so  very  apparent  in 
powder,  and  also  because  much  of  it  is  wasted.  I  recommend 
freshly-made  pills  or  tablets,  coated  in  a  suitable  manner.  If 
these  are  swallowed  in  milk  or  in  water  just  before  a  meal,  the 
taste  of  them  does  not  remain  in  the  mouth  for  more  than 
a  few  seconds.  Personally,  I  always  take  the  drug  thus  in 
preference  to  chocolates,  etc.,  in  which  the  bitterness  seems  to 
me  to  be  rather  increased  than  diminished  by  contrast  to  the 
sweetness  of  the  preparation.  Small  children  can  generally  be 
bribed  to  take  a  pill  by  giving  them  some  small  sweet  afterwards. 

The  experiments  on  the  absorption  and  elimination  of 
quinine  (section  23)  cannot  be  accepted  as  having  answered 
the  question  as  to  which  is  the  best  salt  for  use  in  treatment 
or  prevention.  For  this  purpose  accurate  observations  by 
enumerative  methods,  such  as  we  are  now  adopting,  must  be 
carried  out  at  length.  The  only  answer  to  the  question  can 
be  obtained  by  finding  exactly  how  many  parasites  are  killed 
by  a  given  dose.  I  have  usually  recommended  the  more  soluble 
salts,  because  a  greater  quantity  is  likely  to  be  found  in  the 
blood  at  a   given   moment ;  the   insoluble   salts   are   certainly 


36]  SEGREGATION  285 

absorbed  very  well,  but  probably  not  so  suddenly  as  to  produce 
a  maximum  poisoning  effect  on  the  parasites.  On  the  other 
hand,  the  insoluble  salts  are  likely  to  keep  the  blood  more 
continuously  impregnated  with  the  drug,  and  may  therefore  be 
more  useful  for  general  prevention.  Pending  such  researches, 
it  cannot  be  said  that  one  salt  is  much  more  efficacious  than 
another ;  and  the  salts  selected  must  depend  upon  the  local 
price,  and  the  local  facilities  for  making  up  any  forms  useful  for 
administration.  The  sulphate  is  certainly  the  most  generally 
used  in  British  possessions,  but  the  Italians  have  lately  insisted 
very  strongly  upon  the  tannate,  which  certainly  has  great 
advantages,  being  nearly  tasteless  and  comparatively  cheap. 
Euquinine  is  more  expensive,  and  is  generally  prescribed  in 
doses  of  50  centigrams  for  adults  and  25  centigrams  for  children. 

Arsenic  was  used  long  ago  for  prophylaxis  by  Tommasi- 
Crudeli,  but  has  now  been  abandoned  in  Italy.  We  are  making 
further  experiments  with  atoxyl  and  methylene  blue. 

It  would  be  most  useful  if  some  drug  could  be  found  which 
affects  crescents  more  definitely  than  quinine  does. 

Various  other  agents,  including  serum  of  cattle,  have 
been  tried,  but  the  experiments  will  have  to  be  repeated  by 
enumerative  methods. 

Segregation. — On  going  to  West  Africa  in  1899,  after  service 
in  India,  I  was  much  struck  by  the  fact  that  Europeans  in  the 
former  country  are  not  segregated  as  they  are  in  the  latter.  In 
India  the  British  officials  and  troops  are  nearly  always  housed 
in  separate  locations  commonly  called  cantonments,  so  that 
they  are  frequently  spared  infection  derived  from  neighbouring 
crowded  native  quarters.  But  in  Freetown,  Sierra  Leone,  the 
ofificials  were  oblisred  to  live  almost  in  the  midst  of  the  native 
population,  even  ladies  being  housed  in  rooms  under  which 
native  shops  existed.  I  called  attention  to  this  immediately, 
and  attributed  much  of  the  large  death-rate  amongst  Europeans 
to  it.  The  idea  was  elaborated  by  Stephens  and  Christophers, 
who  added  the  important  consideration  that  native  children  are 


286  PREVENTION  [SECT. 

the  principal  sources  of  the  parasites,  and  J.  E,  Button  strongly 
recommended  segregation  for  Bathurst.  Others  opposed  the 
idea,  because  they  thought  it  would  be  wicked  for  the  Europeans 
to  live  apart  from  their  coloured  brethren. 

At  this  time  the  advisibility  of  reducing  mosquitos  was 
much  disputed  on  the  ground  that  the  insects  diffuse  themselves 
in  all  directions  from  a  breeding  centre,  just  as  particles  of  gas 
diffuse  themselves  from  a  generating  bottle — which  is,  of  course, 
not  the  case.  At  the  same  time  segregation  was  much  urged 
as  an  alternative  measure  ;  but  I  pointed  out  [1904]  that  both 
the  measures  depend  upon  the  same  principle — namely,  that 
mosquitos  do  not  diffuse  themselves  without  limit  from  a  centre. 
That  is,  I  suggested  the  principles  of  random  scatter  given 
in  section  29  (14).  Obviously,  if  mosquitos  spread  to  great 
distances,  local  drainage  will  not  reduce  their  numbers,  and, 
equally  certainly,  segregation  will  not  enable  us  to  avoid  them. 
If  this  were  the  case,  mosquitos  infected  in  native  villages  would 
be  able  to  travel  to  such  distances  that  segregation  would  be 
useless.  Happily,  however,  this  is  not  the  case,  and  therefore 
both  segregation  and  mosquito  reduction  remain  valid. 

We  may  segregate  ourselves  from  the  proximity  either  of 
many  infected  persons  or  of  breeding  -  places.  S.  P.  James 
[1903]  removed  a  number  of  people  from  a  locality  in  which 
Anophelines  abounded  to  one  in  which  they  were  more  scarce. 
In  October  1901,  seventy-eight  children  belonging  to  these 
people  showed  malaria  parasites  in  56%.  In  August  1902  they 
were  all  moved  into  tents  about  600  metres  from  the  nearest 
pool — no  Anophelines  now  being  found  in  the  tents.  The 
result  was  that  not  a  single  case  of  fever  occurred  among 
the  adults,  and  that  on  24th  October  the  height  of  the  fever 
season,  parasites  were  found  only  in  one  out  of  twenty-five 
children  examined  —  and  this  without  treatment  of  any  kind. 
Their  spleen  rate  had  also  decreased  from  75%  in  April  1902 
to  60%  in  October  1902  —  the  splenomegaly  evidently  dis- 
appeared much  more  slowly  than  the  parasite  index. 


37]  MEASURES   FOR   PERSONAL   PROPHYLAXIS  287 

As  proof  of  the  good  effect  of  segregation  from  infected 
persons,  I  think  that  I  may  safely  quote  the  case  of  the  Indian 
cantonments,  where  malaria  is  certainly  much  less  rife  than 
in  the  crowded  native  quarters  in  the  neighbourhood.  Similar 
segregation  has  recently  been  carried  out  in  Sierra  Leone,  where 
a  special  quarter  has  been  provided  for  officials  at  some  distance 
from  Freetown — owing,  I  believe,  largely  to  my  advice  given 
previously. 

I  look  upon  segregation  as  a  most  important  measure  for 
preserving  the  health  of  European  officials,  not  only  against 
malaria,  but  against  many  other  diseases.  It  should  always  be 
adopted  until  sanitation  in  general  arrives  at  a  much  higher  degree 
of  development  in  the  tropics  than  it  has  hitherto  attained. 

37.  Selection  of  Measures  for  Personal  and  Domestic 
Prophylaxis. — The  various  preventive  measures  have  been 
described  in  the  previous  sections  as  briefly  as  possible,  because 
much  more  information  is  given  in  the  important  contributions 
to  this  book  contained  in  the  following  chapter.  But  we  must 
now  discuss  exactly  an  important  matter,  namely,  the  relative 
values  of  these  measures  for  use  under  various  circumstances. 
The  preventive  measures  themselves  are  now  well  known  and 
are  described  in  all  the  text-books  ;  but  mere  description  is  not 
enough,  as  it  is  always  difficult  to  employ  every  one  of  the 
measures,  and  both  the  individual  and  the  health  officer  may 
be  called  upon  to  select  the  most  feasible  ones.  We  have 
to  examine,  first,  the  measures  most  appropriate  for  the  indi- 
vidual— that  is,  for  private  persons,  heads  of  houses,  factories, 
institutions,  ships,  and  so  on ;  and,  secondly,  the  much  more 
complicated  problem  of  the  selection  of  methods  for  public 
prophylaxis. 

(i).  Self -protection  of  Europeans  in  the  tropics. — I  have  had 
experience  on  this  point  during  many  years  and  in  many 
different  countries,  and  have  only  once  been  infected,  and  that 
at  a  time  when  we  did  not  know  how  the  infection  is  produced. 


288  PREVENTION  [Sect. 

I  always  rely  upon  the  possession  of  four  articles,  namely,  a 
good  bed-net,  costing  about  eight  shillings,  a  small  hand-net 
for  catching  mosquitos,  costing  about  one  shilling,  a  palm  leaf 
fan,  costing  one  penny,  and  a  bottle  of  quinine.  With  these 
articles  the  chances  of  becoming  infected  are  reduced  enormously 
— especially  if  a  little  common  sense  and  care  are  added  to 
the  stock. 

I  cannot  speak  too  highly  for  the  ordinary  bed-net,  if  used 
as  directed  in  section  34  (i).  Anophelines  almost  always  bite 
at  night.  If  the  number  of  bites  received  by  two  individuals, 
one  of  whom  always  sleeps  in  a  bed-net,  while  the  other  does 
not  do  so,  could  be  strictly  estimated,  I  think  it  would  be  found 
that  the  latter  receives  only  about  10%  of  the  number  of  bites 
inflicted  upon  the  other.  When  a  person  is  walking  about  in 
the  day  or  in  the  evening  he  is  not  nearly  so  accessible  to  any 
species  of  mosquito  as  when  he  lies  still  and  unconscious  in 
sleep.  It  is  therefore  almost  certain  that  the  large  majority  of 
inoculations  occur  during  sleep,  and  hence,  obviously,  protection 
during  sleep  will  prevent  a  very  large  proportion  of  them. 

Moreover,  I  have  frequently  found  that  persons  who  despise 
bed-nets,  as  many  sportsmen,  soldiers,  planters  and  others  are 
apt  to  do,  are  very  prone  to  suffer  from  malaria.  So  are  those 
who  use  bed-nets  carelessly.  After  service  in  India,  where  most 
people  are  wise  enough  to  guard  themselves  in  this  manner,  I 
was  much  struck  by  the  negligence  on  this  point  of  Europeans 
in  West  Africa.  There  can  be  little  doubt  that  the  comparative 
good  or  bad  health  of  Europeans  in  many  parts  of  the  world 
depends  very  much  on  the  intelligence  which  they  display  in 
this  matter — which  seems  such  a  small  one  to  thoughtless 
people.  Fortunately,  the  public  have  now  been  awakened,  and 
I  have  even  heard  of  several  shipping  and  business  firms  who 
are  wise  enough  to  hold  their  employees  responsible  for 
becoming  infected,  unless  they  can  show  that  they  have  used 
every  precaution.  This  would  be  a  very  good  plan  to  adopt 
generally,  even  by  governments  and  military  authorities. 


37]  MEASURES   FOR    PERSONAL   PROPHYLAXIS  289 

Next  to  the  bed-net,  I  attach  most  value  to  the  small  palm 
leaf  hand-fan  ;  as  stated  above,  I  much  prefer  the  use  of  it  to 
thick  gloves,  mosquito-boots,  etc.  Here  again  the  more  manly, 
but  often  more  unwise  person,  is  apt  to  despise  the  suggestions 
of  common  sense. 

The  small  hand-net  is  almost  equally  valuable.  If  I  sit 
down  to  write  or  read,  I  am  generally  visited  at  once  by  a 
number  of  hungry  suitors,  and  I  like  to  take  the  precaution 
of  catching  and  killing  the  lot  before  proceeding  to  my  task. 
In  fact  I  am  not  ashamed  to  confess  that  I  take  both  a  hand- 
net  and  a  hand-fan  to  bed  with  me,  in  order  to  deal  with  any 
stray  mosquito  which  may  enter  with  me ! 

Protected    by   these  humble    means,   I    do   not   often   have 
recourse  to  quinine.     In  most  places  in  the  tropics  where  large 
numbers  of  Europeans  are  called  upon  to  live,  the  continuous 
use  of  quinine  is   scarcely  demanded.      For  example,   in    the 
Indian  cantonments,  or  the  principal  towns  and  settlements  in 
other  tropical  countries,  the  chances  of  infection  are  too  small 
to  compensate  for  the  discomforts   caused    by  the  drug,  even 
when  given  in  the  best  form  and  in  the  best  way.     It  is,  how- 
ever, another  matter  when  one  is  obliged  to  sleep  in  places  of 
high  endemicity ;   and   here  we   should  always  use  the  drug. 
Medical  men  can  often  be  guided  also  by  the  great  prevalence 
of  Anophelines  ;  and   in  fact  many  of  the  general  public  are 
now  beginning  to  recognise   these   dangerous  insects  by  their 
attitude  and  the  spots   on    their  wings.       If  exposed    in   this 
manner,  or  if  I  think  that  I  may  have  been  bitten  by  infected 
mosquitos,  I  take  the  drug  daily  for  about  a  fortnight  in  doses 
of  between  5-10  grains  (1/3  to  2/3  grammes).     I  know  that  this 
will  not  absolutely  insure  destruction  of  any  protospores  which 
may  have  entered,  but  I  trust  to  luck  that  this  has  been  the 
case.     Anyway,  I  think  that  the  inoculated  germs  have  been  so 
much  reduced  in  numbers  that  (for  certain  reasons  of  my  own) 
I  think   they  are  not  likely  to  produce  a  very  severe  illness, 

T 


290  PREVENTION  [Sect. 

even  if  they  do  reach  the  fever  h'mit.  Then  also  I  am  otherwise 
protected  by  netting. 

How  far  we  should  recommend  what  some  may  consider  to 
be  reprehensible  carelessness  for  the  general  public  is  another 
question.  The  medical  man  does  not  always  adopt  for  him- 
self the  advice  which  he  gives  to  his  patients ;  and  I  therefore 
prefer  to  leave  further  details  under  this  head  to  the  reader. 

The  European  in  the  tropics  must  be  told  that  he  cannot 
insure  himself  against  infection  to  an  absolute  certainty, 
however  careful  he  may  be.  By  bad  luck  he  may  be  bitten 
when  least  expecting  it,  and  by  good  luck  he  may  escape 
altogether,  just  as  the  soldier  may  receive  or  escape  the  fatal 
bullet  in  battle.  Other  precautions  remain  to  be  mentioned. 
If  we  can  select  our  place  of  residence,  we  should,  of  course, 
never  live  in  proximity  to  native  locations,  or  to  marshes,  or  in 
old  tumble-down  thatched  houses,  or  (very  frequently)  in  dirty 
hotels.  One  does  not  therefore  always  welcome  the  hospitality 
of  residents,  however  well  meaning  it  may  be.  For  travellers 
it  is  most  important  to  recommend  that  they  shall  not  go  and 
live  inside  village  houses ;  they  should  always  endeavour  to 
pitch  tents,  both  for  themselves  and  for  their  followers,  in 
appropriate  country  at  some  distance.  Of  course  travellers 
should  always  be  provided  with  mosquito-proof  tents,  both  for 
themselves  and  for  their  men, 

(2),  Domestic  precautions.  —  The  head  of  a  house  should 
enforce  the  various  personal  measures  for  the  whole  of  his 
family  on  the  lines  just  given.  He  should  also  try  to  screen 
a  portion  of  his  house.  In  many  places  this  will  be  difficult, 
because  in  the  tropics  at  least  occupiers  do  not  own  their 
own  houses  and  owners  are  generally  averse  to  paying  for 
such  screening.  But  it  does  not  cost  much  to  screen  a  small 
corner  of  a  veranda  for  sitting  in. 

Next  to  nets,  I  advocate  the  more  general  use  of  punkas  or 
fans.  A  comparison  of  the  life  of  Europeans  in  India  with  it 
in  many  other  tropical  countries  will  force  us  to  admit  their 


37]  CHILDREN   AND   TROOPS  291 

great  value.  Malarial  infection  of  Europeans  is  very  rare  in 
Indian  cantonments,  where  they  use  punkas  almost  day  and 
night,  but  it  is  common  enough  among  planters,  who  are  apt 
to  neglect  them.  I  really  think  that  punkas  prevent  some- 
thing like  50  to  70%  of  infection.  Moreover,  they  keep  the 
body  cool  and  vigorous,  while  without  them  we  remain  covered 
with  perspiration  and  tormented  by  mosquitos  all  day  long. 
So  convinced  am  I  of  the  value  of  punkas  or  fans  for  general 
hygienic  reasons  that  I  would  advocate  the  use  of  them  even 
in  places  where  every  mosquito  has  been  banished. 

The  question  of  prevention  for  European  cJiildren  in  the 
tropics  is  of  the  greatest  importance.  The  difficulty  of  rearing 
them  is  due,  I  think,  partly  to  the  great  heat,  partly  to  malaria, 
and  partly  to  various  entozoa  and  other  diseases.  Those  who 
can  afford  screening  and  punkas  should  therefore  employ  them 
for  their  children  at  whatever  cost.  If  they  cannot  afford  them, 
they  should  not  bring  their  children  to  the  tropics.  The  habitual 
use  of  prophylactic  quinine  is  seldom  seen  among  European 
children  in  the  tropics,  and  I  doubt  whether  it  can  be  generally 
recommended.  In  fact,  if  such  use  is  actually  required,  the  place 
should  be  considered  too  malarious  for  children.  Of  course  it 
is  another  matter  if  children  have  already  become  infected. 

(3).  Troops  on  service. — The  amount  of  baggage  allowed  is 
always  very  small,  but  the  last  article  to  be  dispensed  with 
should  be  the  bed-net.  In  my  opinion  the  military  authorities 
should  make  all  efforts  to  provide  every  man  with  one,  because 
the  cost  due  to  loss  of  strength  in  consequence  of  invaliding 
from  malaria  must  always  be  vastly  in  excess  of  that  of  the 
purchase  and  transport  of  nets.  The  disease  has  caused  well- 
known  disasters  to  troops,  as  in  the  British  Walcheren  expedi- 
tion and  the  French  expeditions  in  Madagascar  (section  60). 
On  the  other  hand,  the  American  troops  in  the  Philippines  used 
nets  and  admitted  their  great  value.  Where  the  authorities 
fail  in  providing  them  the  wise  soldier  will  do  well  to  follow  the 
old  maxim  of  "  self-help."     A  daily  quinine  ration  of  say  5  grains 


292  PREVENTION  [Sect. 

every  morning  should  also  be  insisted  upon,  together  with  the 
rigorous  use  of  nets.  I  scarcely  think  that  gloves  and  veils, 
such  as  Laveran  figures  as  used  among  the  Japanese  troops, 
are  so  urgently  demanded — at  least  in  the  tropics,  where  they 
would  be  nearly  intolerable.  The  Medical  Department  has  the 
care  of  choice  of  proper  bivouacs  and  quarters.^ 

(4).  Ships. — I  always  carry  a  net  which  can,  if  required,  be 
hung  over  the  bunk.  Ships  in  the  tropics  often  delay  for 
hours  or  days  in  port,  and  are  frequently  visited  by  swarms 
of  mosquitos.  Of  course,  all  ships  owned  by  companies  who 
possess  any  degree  of  humanity  and  intelligence  should  be 
invariably  screened  against  mosquitos  in  the  manner  shown 
by  Dr  Wolferstan  Thomas  (section  46). 

Quinine  should  be  always  given  to  the  crew  on  arrival  at 
the  first  malarious  port,  and  for  at  least  one  month  after  leaving 
the  last  one,  if  the  voyage  lasts  so  long.  The  great  mistake 
of  stopping  the  drug  on  departure  from  the  malarious  coast  is 
often,  indeed  generally,  made.  Many  of  our  nautical  patients 
in  Liverpool  give  histories  of  having  been  attacked  for  the  first 
time  when  nearing  the  British  coast — that  is,  their  infections 
had  been  received  weeks  previously,  but  had  been  suppressed 
by  the  drug  until  the  use  of  it  was  abandoned. 

(5).  Hospitals  and  asylums. — Here  quinine  cannot  be  given 
without  interfering  with  the  treatment  of  the  various  kinds 
of  disease  present.  The  superintendent  must  see  to  it  that 
mosquitos  are  not  being  bred  within  the  hospital  premises ; 
but  unless  mosquito  reduction  has  been  adopted  for  a  con- 
siderable radius  outside  the  institution,  screening  should  be 
adopted  as  well.  Hospitals  with  crowded,  unprotected  wards 
furnish  the  worst  examples  of  congregate  sleeping  (section  28 
(3)),  so  favourable  to  the  mosquito  transference  of  several 
diseases.  For  example,  dengue  prevailed  greatly  in  an  un- 
protected hospital  in  the  Philippines,  while  it  was  absent  from 
a  protected  one ;  and  I  have  frequently  found  filariae  and 
^  See  destruction  of  adult  mosquitos,  p.  362. 


37]  BARRACKS  293 

Plasmodia  in  hospital  mosquitos.  In  fact  the  dangers  are  so 
great  that  it  is  perhaps  better  to  advise  that  every  hospital 
should  be  screened  whether  mosquito  reduction  is  carried  out 
or  not.  A  mosquito  -  infested  hospital  is  a  most  disgraceful 
thing.  The  miserable  defenceless  people  it  contains  are  in- 
fected in  the  very  place  where  they  have  come  to  be  cured, 
and  there  is  no  excuse  for  it. 

(6).  Barracks. — Unless  mosquito  reduction  can  be  rendered 
very  thorough,  the  best  plan  is  perhaps  to  employ  screening  as 
well.  Probably  most  of  the  inoculations  occur  at  night,  largely 
in  consequence  of  the  congregate  sleeping  usually  adopted  in 
barracks.  The  cost  of  death  and  invaliding  of  soldiers  is 
probably  far  in  excess  of  that  of  screening.  Bed-nets  are  now 
being  often  used  or  advocated,  even  for  native  soldiers  ;  and  I 
have  heard  of  several  cases  where  officers  have  helped  their  men 
to  purchase  them.  But  surely  it  is  the  duty  of  the  military 
authorities  to  provide  screening  instead.  Enormous  sums  are 
frequently  wasted  on  the  erection  of  new  barracks — sums  which 
would  have  sufficed  to  screen  all  the  barracks  in  a  country. 
The  neglect  on  this  point  is  simply  marvellous.  In  one  case, 
known  to  me  personally,  a  serious  epidemic  of  malaria  occurred 
because  the  authorities  were  disputing  as  to  who  should  pay  for 
the  hooks  required  to  hang  the  bed-nets  (already  purchased  !). 
Several  of  the  men  died,  and  a  number  were  invalided  at  a  cost 
which  afterwards  sufficed  to  drain  the  whole  neighbourhood. 

Punkas  pulled  by  machinery  have  long  been  in  use  in  many 
military  hospitals  and  barracks  in  India. 

Unless  screening  is  very  perfect,  great  care  must  be  taken  to 
complete  the  extermination  of  the  parasites  in  infected  soldiers. 
In  any  case  this  is  necessary  in  order  to  maintain  the  effec- 
tive fighting  strength,  because  soldiers  "  soaked "  with  malaria 
are  only  a  source  of  expense  in  war.  I  doubt  whether  the 
six  weeks'  treatment  used  in  India  is  quite  sufficient.^ 

Of  course  a  large  proportion  of  the  infections  among  troops 

^  See  H.  H.  Johnston,  Brit.  Med.  Journ.,  15th  August  1908. 


294  PREVENTION  [Sect. 

are   often    contracted    outside    barracks.      The    question    then 
becomes  one  of  public  prophylaxis  (section  39). 

The  quarters  of  officers  and  families  should,  in  my  opinion, 
be  always  screened  unless  mosquito  reduction  is  very  perfect. 

In  the  old  days,  in  British  possessions,  large  areas  round 
barracks  were  kept  strictly  under  the  cantonment  authorities, 
who  refused  to  allow  the  general  populace  to  live  in  them. 
Unfortunately,  owing  to  the  pernicious  sentimental  outcries 
which  are  proving  so  destructive  to  vigour  and  prosperity,  this 
wise  rule  is  now  tending  to  fall  out  of  use  ;  filthy  huts  spring  up 
close  to  the  barracks  ;  the  troops  become  heavily  infected  with 
malaria  and  other  diseases  ;  and  the  nation  which  gives  way  to 
this  brainless  folly  has  to  pay  much  more  for  its  military  service, 
and  may  have  to  pay  still  more,  some  day,  for  military  defeat. 

(7).  Prisons.  —  The  prisoners  are  taken  from  the  lowest 
populace,  and  are  being  constantly  changed  as  sentences 
expire.  Hence  large  numbers  of  them  are  infected  outside, 
and  the  principal  measure  is  case  reduction.  In  addition  to 
this,  screening  or  mosquito  reduction,  or  both,  should  be 
adopted  according  to  circumstances. 

(8).  Schools.  —  Boarding  schools  are  scarce  in  malarious 
countries.  Day  schools  give  a  most  valuable  opportunity,  not 
only  for  dealing  with  malaria  by  case  reduction,  but  also  for 
measuring  it ;  but  this  matter  is  part  of  the  general  plan  of 
campaign  (section  40  (6)), 

(9).  General  rules. — In  all  matters  of  domestic  prophylaxis 
it  is  wise  to  remember  the  following  rules  (which  cannot  be 
repeated  too  often) : — {a)  unless  there  is  strong  prima  facie 
reason  to  believe  that  cheap  measures  must  fail,  always  begin 
with  them  before  attempting  more  expensive  ones  ;  and  {h)  do 
not  adopt  any  measure  until  careful  examination  has  proved 
the  necessity  for  it.  For  example,  I  have  seen  and  heard  of 
expensive  screening  being  installed  {a)  where  a  little  mosquito 
brigade  work  would  have  cleared  the  mosquitos  entirely,  and  {b) 
where  most  of  the  infections  were  really  being  acquired  outside. 


38]  SANITARY   AXIOMS  295 

38.  General  Sanitary  Axioms.  —  Before  we  consider  the 
complex  subject  of  public  malaria  prevention,  it  is  advisable 
to  state  the  following  series  of  propositions  regarding  the  pre- 
vention of  all  diseases. 

(i).  Widespread  diseases,  especially  endemic  diseases,  cause 
much  pain,  sorrow,  expense  and  loss  of  prosperity 
to  the  people. 

(2).  Next  to  the  maintenance  of  the  State,  it  is  the  duty 
of  scientific  governments  to  investigate  their  mode 
of  propagation,  and  to  endeavour  to  control  them. 

(3).  For  economic  reasons  alone,  governments  are  justified 
in  spending  for  the  prevention  of  such  diseases  a 
sum  of  money  equal  to  the  loss  which  the  diseases 
inflict  upon  the  people. 

(4).  The  amount  of  money  spent  on  the  prevention  of  various 
diseases  should,  ceteris  paribus,  be  proportioned  to 
the  amount  of  sickness  and  mortality  caused  by  each. 

(5).  It  is  the  duty  of  governments  to  make  and  to  enforce 
ordinances  required  for  the  prevention  of  diseases  ; 
and  of  the  people  to  submit  to  them. 

(6).  Cete7'is  paribus,  that  sanitary  measure  is  the  wisest 
which  causes  the  public  the  least  inconvenience. 

(7).  Ceteris  paribus,  that  measure  is  the  most  practicable 
which  can  be  carried  out  by  governments  without 
making  any  demands  at  all  on  the  thoughts,  efforts 
or  compliance  of  private  persons. 

(8).  Ceteris  paribus,  that  measure  is  the  most  economical 
which  confers,  for  unit  of  cost,  the  widest  benefits 
on  the  public. 

(9).  For  the  prevention  of  diseases  on  a  large  scale  a  suit- 
able expert  organisation  is  always  required. 
(10).  It  is  always  advisable  to  carry  out  accurate  and 
repeated  measurements  of  the  prevalence  of  the 
disease  which  we  propose  to  prevent ;  of  the  cost 
of  the  adopted  measures  ;  and  of  their  results. 


296  PREVENTION  [Sect. 

Written  out  in  this  manner  these  statements  appear  trite 
enough  ;  but  in  my  experience  every  one  of  them  is  forgotten 
in  actual  administration.  Thus  few  persons  remember  the  first 
axiom — until  they  themselves  are  taken  ill.  Few  governments 
really  attend  to  the  second  one.  Scarcely  any  one  has  con- 
ceived the  simple  idea  contained  in  the  third,  and  it  is  the  rule 
to  grudge  spending  a  hundred  pounds  for  a  disease  which  costs 
thousands.  Dramatic  diseases  interest  many,  while  common 
ones  are  forgotten  ;  and  the  remaining  axioms  are  too  often 
overlooked  even  by  those  who  direct  or  discuss  sanitary  work. 

39.  Selection  of  Measures  for  Public  Prevention.— From 

the  fundamental  reasoning  in  sections  28  and  33,  and  also  from 
general  experience  in  many  countries  during  the  last  ten  years, 
we  are  now  probably  justified  in  making  the  following  state- 
ments : — That  malaria  can  be  completely  extirpated  in  a  locality 
by  the  complete  adoption  of  any  one  of  the  three  great  pre- 
ventive measures,  namely,  protection,  mosquito  reductioti,  and 
treatment.  That  is  to  say,  if  every  person  in  the  community 
could  be  fully  guarded  against  mosquito  bites,  or  if  every 
Anopheline  could  be  banished,  or  if  every  infected  person  could 
be  thoroughly  treated  from  the  beginning  of  his  case,  then  each 
of  these  measures  ought  to  suffice  by  itself  to  banish  the  disease 
entirely.  Moreover,  if  we  could  use  two  of  the  measures,  or  all 
of  them,  the  result  would  be  still  more  assured. 

But,  obviously,  it  will  never  be  possible  in  any  general 
community  to  adopt  or  to  enforce  any  one  of  these  measures 
completely.  Thus,  however  carefully  mosquito-nets  or  screening 
are  used,  many  people  will  still  continue  to  be  bitten  occasion- 
ally, so  long  as  the  mosquitos  are  allowed  to  remain.  Again, 
however  carefully  we  may  destroy  every  mosquito  which  we 
can  catch,  or  every  larva,  or  remove  the  principal  breeding- 
places,  still,  a  few  insects  and  breeding-places  are  sure  to  escape 
us.  Thirdly,  however  strongly  we  may  urge  suitable  treatment 
of  all   infected    persons,   a    few  are   sure   to    resist   it,   and   to 


39]  MEASURES    FOR   PUBLIC   PREVENTION  297 

spread  the  disease  if  any  Anophelines  are  left.  Hence,  though 
theoretically  possible,  the  complete  use  of  any  one  of  the 
measures  is  not  really  practicable. 

Fortunately,  however,  we  can  see  by  careful  consideration 
of  the  principles  laid  down  in  section  28  that  complete  eradica- 
tion of  malaria  may  still  be  possible  by  the  adoption  of  each 
measure  by  itself,  even  if  that  measure  is  not  completely  given 
effect  to.  By  that  section  we  see  that  the  static  malaria 
(section  30)  will  tend  to  vanish,  not  only  if  all  the  factors  of  the 
equation  are  rendered  absolutely  prohibitive,  but  also  if  they 
are  reduced  to  a  certain  figure  ;  that  is,  if  the  new  infections 
can  no  longer  keep  pace  with  the  natural  recoveries.  This 
important  and  encouraging  law  has  been  well  exemplified  in 
Great  Britain,  from  which  the  disease  has  entirely  disappeared 
owing  to  partial  and  indeed  almost  unconscious  agencies,  as 
described  in  section  30  (21). 

Lastly,  we  can  understand  from  the  same  reasoning  that  a 
partial  adoption  of  any  one  of  the  measures,  though  it  may 
not  banish  malaria  absolutely,  is  still  likely,  or  indeed  certain, 
to  make  some  reduction  in  the  disease  provided  that  the  other 
factors  remain  unchanged. 

All  these  truths  still  continue  to  apply  if  we  adopt  not  one 
single  measure,  but  several  combined.  Thus  it  may  well  be 
that  an  extremely  partial  application  of  two  of  the  measures 
will  produce  results  as  good  as  a  less  partial  application  of  one 
of  them  would  have  done  ;  and  this  fact  may  help  us  to  do  the 
work  much  more  economically. 

Thus  the  head  of  a  sanitary  department  who  intends  to 
carry  out  a  large  campaign  is  fortunately  able  to  avail  himself 
of  several  measures  or  combination  of  measures,  by  any  one  of 
which  his  purpose  may  be  effected.  But  he  has  to  consider 
means  as  well  as  objects  :  his  duty  to  his  Government  demands 
that  he  should  spend  as  little  money  as  possible,  and  his  duty 
to  the  people  demands  that  he  should  not  trouble  them  too 
much.     Still  more  important,  the  various  measures  are  more  or 


298  PREVENTION  [Sect. 

less  practicable  according  to  a  number  of  local  conditions,  all 
of  which  must  be  carefully  considered  by  him  before  he  comes 
to  a  decision.  In  practical  sanitary  politics,  therefore,  the  mere 
enumeration  and  general  description  of  the  various  measures 
are  quite  insufficient,  and  we  are  obliged  to  discuss  with  great 
care  their  relative  values  under  different  circumstances.  The 
reader  can  assure  himself  still  further  of  this,  by  studying  the 
numerous  contributions  given  by  the  most  eminent  men  in 
the  following  chapter.  He  will  see  that  different  measures 
are  being  adopted  in  different  countries.  In  some  countries, 
especially  Panama,  Egypt,  Durban  and  the  Federated  Malay 
States,  mosquito  reduction  is  the  principal  measure.  In  others, 
especially  Italy,  Greece  and  the  German  and  French  possessions, 
prevention  by  treatment  is  the  favourite  remedy  ;  and  in  other 
places  combined  measures  are  in  use.  In  fact  there  has  been 
much  discussion  upon  this  point  during  the  last  ten  years  ; 
some  urge  one  measure  and  some  urge  others — each  being 
guided  by  his  own  experience  in  his  own  malarious  country. 
The  truth  is  that  all  the  measures  are  good  and  useful,  and 
that  each  is  most  suitable  under  certain  circumstances.  The 
subject  is  evidently  a  complex  one.  I  will  try  to  make  the 
issues  as  clear  as  possible  by  supposing  at  first  that  each 
measure  is  to  be  adopted  by  itself  alone. 

Protection  (section  34)  requires  the  use  of  bed-nets,  screen- 
ing, fans  and  some  other  devices.  It  demands  an  entire 
concurrence  of  the  people  who  are  to  be  protected.  Probably 
no  government  can  force  the  public  to  protect  themselves. 
Although  the  rich  may  be  quite  willing  to  do  so  by  bed-nets 
or  screening,  the  poor  will  generally  refuse  the  expense  incurred. 
The  cost  of  a  good  bed  -  net  is,  for  instance,  equal  to  the 
monthly  pay  of  a  day  labourer  in  India.  The  cost  of  screen- 
ing a  house  completely  is  often  more  than  a  tenant  cares  to 
incur,  and  the  house  owner  generally  refuses  to  undertake  it 
for  tenants  who  occupy  their  houses  on  short  leases  (as  gener- 
ally happens    in    the   tropics).      Punkas  and  fans  are  scarcely 


39]  PROTECTION  299 

practicable  for  the  poor,  and  medicinal  culicifuges  are  of  little 
value.  In  most  countries  the  poor,  especially  in  rural  districts, 
are  badly  housed  in  huts  which  are  everywhere  permeable  to 
mosquitos.  To  protect  such  houses  by  any  known  means  will 
generally  cost  as  much  as  rebuilding  the  whole  house.  Even 
if  the  state  would  be  willing  to  provide  every  householder  with 
a  bed-net  for  himself  and  his  family,  it  would  still  have  to  make 
arrangements  for  the  constant  repair  of  them,  while  they  would 
often  remain  unused.  We  can  scarcely  expect  that  poor 
families,  living  crowded  together  in  a  single  chamber,  will  ever 
exert  themselves  to  use  mechanical  protection  in  a  careful  way. 
But  even  with  the  most  complete  protection  of  houses,  people 
will  still  be  subject  to  being  bitten  out-of-doors. 

This,  however,  is  to  look  at  the  subject  only  from  the  darker 
side.  As  already  stated,  even  a  partial  protection  is  quite 
likely  to  have  an  immense  effect  on  the  malaria.  Even  if  only 
a  proportion  of  the  people  could  be  persuaded  to  use  an)-  care 
in  protection,  doubtless  the  new  infections  would  be  reduced  so 
much  that  the  static  malaria  might  either  disappear  entirely  or 
become  very  small.  It  is,  therefore,  most  advisable  to  urge  pro- 
tection as  strongly  as  possible ;  to  advocate  suitable  housing 
for  the  poor  ;  and  to  post  notices  for  the  information  of  the 
public  regarding  the  dangers  of  being  bitten  by  mosquitos. 

We  see,  then,  that  the  measure  of  general  protection  against 
mosquitos  is  scarcely  capable  of  more  than  a  very  partial 
adoption  by  the  public.  As  a  Government  measure  it  is 
opposed  to  the  seventh  sanitary  axiom  given  above.  Although 
it  possesses  what  some  governments  may  consider  to  be  an 
advantage,  namely,  that  it  does  not  make  direct  demands  upon 
their  own  finances,  it  may  yet  be  in  the  end  more  costly  to  the 
public  than  other  measures.  In  most  countries  the  number  of 
houses  is  equal  to  about  1/4  or  1/5  of  the  total  population — that 
is  to  say,  the  houses  are  very  numerous.  The  cost  of  screening 
each  house  or  of  providing  all  the  innates  with  mosquito-nets 
will  therefore  mount  up  to  a  very  large  sum.     Thus  in  a  city 


300  PREVENTION  [Sect. 

of  30,000  inhabitants,  there  are  hkely  to  be  6,000  houses,  and  if 
the  average  cost  of  screening  each  house  amounts  to  only  £1, 
the  total  cost,  including  that  of  maintenance,  will  be  very  large. 
I  doubt  whether  any  form  of  screening  for  the  poor  will  not 
depreciate  at  the  rate  of  50%  per  annum.  It  may  therefore 
happen  that  the  total  cost  will  greatly  exceed  that  of  mosquito 
reduction  or  treatment.  Even  if  it  does  not  exceed  that  of 
mosquito  reduction,  the  advantages  of  the  latter  are  so  great 
that  it  would  be  preferable  to  adopt  it  (if  it  is  feasible). 

So  much  for  protection  as  a  general  measure  ;  but  it  is  often 
decidedly  called  for  under  special  circumstances,  as  for  isolated 
houses  in  the  country,  especially  in  proximity  to  marshes  ;  and 
for  hospitals,  barracks,  prisons,  hotels,  travellers'  rest-houses, 
tents,  ships,  river-boats,  and  so  on. 

For  general  prophylaxis,  especially  in  crowded  localities, 
Anopheline  reduction  has  many  great  advantages,  which  I  have 
often  pointed  out.  Practically,  Anopheline  reduction  may  be 
generally  merged  into  the  wider  measure  of  mosquito  reduction, 
which  costs  little  more  to  effect  and  adds  greatly  to  the  benefits 
obtained.  It  is  essentially  the  radical  measure,  which  tends  to 
remove  not  only  the  carriers  of  the  disease  but  also  a  continual 
source  of  annoyance  to  the  public.  As  mosquitos  are  known  to 
carry  other  diseases,  namely,  yellow  fever,  filariasis,  and  almost 
certainly  dengue,  mosquito  reduction  will  probably  do  much 
more  even  than  to  reduce  malaria.  To  the  practical  hygienist 
it  has  still  greater  claims  for  consideration,  especially  because  it 
conforms  perfectly,  not  only  with  the  eighth  sanitary  axiom, 
but  also  with  the  sixth  and  seventh — which  is  not  the  case  with 
some  of  the  other  measures.  For  example,  a  government  or 
municipality  can  maintain  men  for  the  purpose  of  removing 
breeding  -  places  without  causing  any  trouble  at  all  to  the 
populace.  A  certain  amount  of  legislation  is  required  to 
control  obstinate  people  who  sometimes  refuse  out  of  wilfulness 
to  allow  sanitary  agents  into  their  premises  ;  but  beyond  this 
it  is  generally  advisable  for  the  authorities  to  do  everything  as 


39]  MOSQUITO   REDUCTION  301 

regards  mosquito  reduction  for  themselves.  No  one  is  asked  to 
believe  in  the  mosquito  theory,  or  to  take  drugs,  or  to  protect 
himself  and  his  family  with  bed-nets,  or  to  put  screens  to  his 
windows.  Nor  does  mosquito  reduction  cause  much  or  any 
inconvenience  to  the  public  (axiom  6).  Occasionally  cultivation 
in  proximity  to  towns  must  be  controlled,  and  pits,  cisterns, 
wells,  etc.,  used  for  irrigation  must  be  dealt  with  ;  but  compensa- 
tion for  any  harm  done  must  be  paid  for  by  the  authorities, 
and,  where  mosquito  reduction  is  generally  feasible,  only  a 
small  proportion  of  the  people  are  affected  in  such  matters. 
Lastly,  mosquito  reduction  has  the  advantage  (which  is  not 
always  recognised)  that  it  compels  the  sanitary  authorities 
always  to  maintain  a  minute  inspection  of  the  area  under  their 
care,  compels  cleaning  of  all  premises,  removal  of  waste  water, 
proper  maintenance  of  roads,  and  so  on  (section  35). 

Practically,  however,  questions  of  cost  and  feasibility  have 
to  be  considered.  It  is  almost  impossible  to  give  an  estimate 
of  the  cost  of  mosquito  reduction,  which  may  depend  every- 
where on  the  nature  of  the  soil,  the  slope  of  the  ground,  the 
rainfall,  the  vegetation,  the  existence  of  marshes,  the  character 
of  the  drainage  and  of  the  sanitary  department  already  in  use, 
and  so  on.  Quite  possibly,  although  the  necessary  expenditure 
is  really  within  the  capacity  of  the  local  budget,  the  authorities 
may  not  think  so  at  the  moment,  so  that  the  health  officer 
is  left  powerless  to  adopt  this  measure.  The  advantage  of 
mosquito  reduction,  that  it  can  be  carried  out  entirely  by  the 
state,  has  a  corresponding  disadvantage,  namely,  that  the  state 
imagines  that  it  alone  pays  for  the  work.  In  a  perfect  govern- 
mental machine,  the  state  could  immediately  call  for  increased 
taxes  in  consequence  of  any  work  of  absolute  public  necessity ; 
but  in  this  very  imperfect  world,  the  public  is  apt  to  be  rather 
blind  in  these  matters,  and  the  state  is  afraid  of  arousing 
hostility,  even  by  saving  people's  lives.  At  the  same  time  it  is 
proper  to  note  over  and  over  again  that  mosquito  reduction 
often   really  does    not  cost  as   much    as   some   pretend.     The 


302  PREVENTION  [Sect. 

figures  for  Ismailia  and  the  Federated  Malay  States  include 
large  items  in  excess  of  the  actual  anti-mosquito  campaign,  that 
is,  items  for  general  drainage,  for  building  sites  or  cultivation 
purposes  ;  and  those  for  Panama  are  so  mixed  that  wc  cannot 
exactly  extricate  the  cost  of  this  measure  by  itself^  Moreover, 
by  the  general  principles  of  section  28,  malaria  may  be  com- 
pletely reduced  even  by  a  partial  reduction  of  the  Anophelines 
below  the  necessary  limit  (which  I  have  roughly  estimated  to 
be  about  40  different  Anophelines  per  head  per  month) ;  and  it 
may  be  partially  reduced  even  by  a  smaller  reduction  of  the 
insects.  In  fact  the  small  measures  under  the  head  of  minor 
works  generally  cost  but  very  little,  and  though  they  may  not 
suffice  for  complete  mosquito  reduction,  are  still  likely  to  do 
much  good,  especially  if  combined  with  other  precautions. 

Prevention  by  treatment  also  has  many  advantages.  In 
every  locality,  even  if  every  mosquito  can  be  banished,  a 
number  of  cases  are  likely  to  continue  to  suffer  from  relapses 
for  many  months,  and  these  always  require  careful  treatment. 
Hence  case  reduction  should  always  be  adopted  as  much  as 
possible,  whether  the  other  measures  are  used  or  not.  Such 
case  reduction  can  hardly  come  within  the  sixth  and  seventh 
sanitary  axiom,  because  no  inconvenience  or  trouble  is  inflicted 
on  the  people  by  gratuitous  treatment  of  their  sickness. 
Another  great  advantage  is  that  the  measure  can  be  com- 
menced, even  on  a  somewhat  large  scale,  by  medical  men, 
without  making  any  immediate  large  demands  on  the  public 
purse.  As  shown  in  Italy  and  Greece,  the  mere  sale  of  quinine 
at  cost  price  by  Government  produces  an  excellent  effect,  if  the 
people  are  intelligent  enough  to  use  it.  Moreover,  medical 
men  who  are  now  best  acquainted  with  the  whole  theory  of 
malaria,  are  precisely  those  who  carry  out  this  measure.  In 
fact  their  practice  actually  receives  some  benefit  by  it,  at  least 
at  first ;  they  are  accustomed  to  the  use  of  drugs,  and  they  find 
no  difficulty  in  urging  their  patients  to  take  quinine. 

'  Col.  Gorgas  says  $2"o  a  head  (secLion  42). 


39]  BY   TREATMENT  303 

Unfortunately,  all  this  does  not  apply  in  many  countries 
in  which  the  number  of  qualified  medical  men  is  very  small. 
In  many  other  countries  the  natives  object  entirely  to  our  forms 
of  treatment,  and  rebel  even  against  quinine.  Still  further, 
many  people  are  afraid  of  admitting  the  existence  of  domestic 
illness  amongst  their  children,  or  will  not  take  the  trouble  to 
treat  them  at  all.  Others,  again,  refuse  to  buy  quinine,  even 
at  the  cheapest  rates,  or  cannot  afford  the  time  to  attend 
hospitals  or  dispensaries  for  it,  so  that  inefficient  doses  are 
frequently  taken,  with  the  result  that  the  patients  become 
sceptics  as  to  the  value  of  the  drug,  and  advise  their  friends 
against  it.  In  fact,  these  practical  difficulties  are  so  great  that, 
as  I  stated  in  my  Mauritius  report,  we  are  obliged  in  the  tropics 
to  distribute  the  drug  gratis  from  house  to  house  if  we  wish  to 
obtain  any  material  benefit  from  it.  Lastly,  if  we  propose  to 
confine  ourselves  only  to  case  reduction,  that  is,  to  the  treatment 
of  the  sick,  we  have  to  distinguish  the  sick  from  the  healthy, 
which  generally  can  be  done  only  by  medical  men,  or  by 
qualified  assistants  at  the  cost  of  considerable  and  continued 
labour. 

This  trouble  is  saved  if  the  public  can  be  persuaded  to 
adopt  not  only  case  reduction,  but  also  quinine  prophylaxis — 
that  is,  the  treatment  of  persons  who  have  not  yet  shown 
signs  of  illness,  but  may  possibly  have  become  infected. 
Unfortunately,  if  there  are  difficulties  in  the  way  of  treating 
the  sick,  there  are  sure  to  be  still  greater  difficulties  in  the 
way  of  persuading  healthy  persons  to  take  any  form  of  quinine 
continuously.  Poor  and  ignorant  natives,  and  indeed  many  other 
people,  object  strongly  to  this  course.  Some  say  that  they  would 
actually  prefer  the  occasional  chance  of  malaria  to  a  continued 
certainty  of  dyspepsia.  It  is  true  that  if  quinine  is  given  daily 
in  small  doses  it  produces  much  less  physiological  effect ;  but 
in  the  majority  of  persons  it  always  does  produce  some  slight 
inconvenience.  Busy  people,  hard-worked  labourers  or  mothers 
of  families  tend    to   rebel    very  much    against   any    continued 


304  PREVENTION  [Sfxt. 

medication.  We  know  in  Europe  how  much  people  are  apt 
to  protest  against  vaccination — a  single  simple  operation  causing 
scarcely  any  discomfort,  and  protecting  for  years  against  a 
dangerous  and  disfiguring  disease ;  how  much  more,  therefore, 
will  people  be  apt  to  protest  against  a  medicine  which  must 
be  taken  daily  for  months  during  the  malaria  season,  even 
if  they  are  not  affected  by  the  disease.  Of  course,  persons 
who  remain  infected,  specially  children,  always  continue  to  be 
a  danger  to  their  neighbours,  and  for  this  reason  alone  a 
complete  reduction  of  malaria  by  treatment  must  always  be 
difficult,  unless  the  authorities  have  such  power  that  they  can 
actually  force  the  drug  down  the  throats  of  the  people.  This 
is  often  possible  in  the  case  of  soldiers,  employees  of  companies, 
or  coolies  on  plantations,  but  scarcely  for  the  general  public. 

On  the  other  hand,  we  may  rest  assured,  though  complete 
case  reduction  is  seldom  practicable,  that  the  partial  measure 
is  certain  to  do  much  good.  Because  we  cannot  force  all  the 
people  to  take  quinine,  that  is  no  reason  why  we  should  not 
persuade  as  many  as  possible  to  do  so. 

Segregation,  either  from  marshes  or  from  infected  persons, 
should  not  be  looked  upon  as  a  measure  of  general  public 
prevention,  as  it  is  applicable  only  in  a  few  cases. 

Next,  let  us  compare  the  measures  two  and  two — at  the 
risk  of  repetition.  First,  suppose  that  we  have  to  deal  with 
an  ideal  country  where  all  the  measures  are  equally  feasible, 
and  will  cost  the  same  sum  of  money — a  thing  which,  of  course, 
never  happens. 

Protection  is  evidently  at  a  disadvantage  compared  with 
mosquito  reduction.  It  will  never  entirely  prevent  the  bites 
of  mosquitos ;  nets  and  screens  always  require  some  trouble 
to  keep  in  order,  and  certainly  add  somewhat  to  the  heat- 
often  so  unbearable  in  the  tropics.  On  the  other  hand,  mosquito 
reduction,  if  sufficient,  removes  at  once  an  incubus,  a  veritable 
plague — we  breathe,  move  and  sleep  freely,  our  children  are 
safe,  our  verandas  and  gardens  open  to  us. 


39]  COMPARISONS  305 

Now,  compare  protection  with  prevention  by  quinine.  The 
former  guards  us  not  only  against  all  mosquito-borne  diseases, 
but  against  constant  personal  annoyance  ;  the  latter,  only  against 
malaria.  Nets  and  screens  cause  no  dyspepsia,  no  ringing  in 
the  ears,  and  no  daily  trouble  with  the  children.  I  think  that 
every  one  will  prefer  freedom  both  from  mosquitos  and  from 
dyspepsia  to  the  inflictions  of  both.  Hence  protection  has 
great  advantages.  But,  in  spite  of  this,  the  sick  must  still 
be  treated. 

Mosquito  reduction  has  all  the  advantages  of  protection 
and  more,  and  is  therefore  greatly  preferable  (under  our 
hypothetical  conditions)  to  quinine.  But,  nevertheless,  the 
sick  must  still  be  treated. 

Ideally,  therefore,  mosquito  reduction  is  by  far  the  best 
measure.     Protection  is  next,  and  quinine  last. 

Now,  let  us  consider  the  measure  from  the  point  of  view 
of  cost  and  feasibility.  The  cost  of  protection  must  obviously 
vary  according  to  the  number  of  houses,  which  can  be  roughly 
ascertained  by  dividing  the  population  by  about  four  or  five. 
In  Mauritius  at  the  census  of  1901  the  population  was  373,336, 
and  there  were  93,031  houses,  so  that  there  were  about  4*25 
persons  to  each  house  on  the  average.  Probably  the  cost  of 
protecting  a  single  house  there  would  be  quite  £1  on  the 
average,  as  a  very  low  estimate,  amounting  to  ^^93,031  (about 
1,500,000  rupees)  for  the  whole  island.  Besides  this,  repairs 
and  renewals  of  the  screens  and  nets  would  probably  amount 
to  quite  2$/^  of  the  original  cost  at  a  low  estimate;  so  that 
after  the  first  installation  of  the  protection  an  annual  cost  of 
;^23,ooo  (350,000  rupees)  would  have  to  be  incurred  for  the 
mechanical  work  of  supervision.  This,  of  course,  is  a  very 
rough  estimate,  and  quite  possibly  more  than  £1  would  be 
required  to  protect  each  house  on  the  average,  because  many 
of  the  poorest  houses  are  little  better  than  shelters  of  mud  and 
thatch.  Regarding  the  feasibility  of  protection,  I  repeat  that 
it  cannot  be  forced  by  Government  on  the  people  except  as 

U 


3o6  PREVENTION  [Sect. 

regards  employees  of  planters,  railway  companies,  etc.  Officials 
cannot,  therefore,  have  any  resource  except  to  persuade  and 
to  keep  on  persuading,  and  even  then  only  a  proportion  of 
the  people  would  adopt  the  measures.  For  anything  like 
general  protection  the  Government  would  probably  have  to 
supply  most  of  the  cost — which  we  have  seen  will  be  very 
considerable.  Of  course,  in  Europe  and  the  United  States, 
where  the  people  have  reached  a  higher  degree  of  prosperity 
than  in  most  tropical  countries,  this  measure  is  more  likely  to 
be  adopted  by  the  general  public  ;  but  even  in  them  the  very 
poor  and  the  agricultural  classes  are  likely  to  cause  great 
difficulties.  It  can,  therefore,  scarcely  be  said  that  general 
protection,  or  even  protection  of  a  percentage  of  houses,  is  an 
easy  and  cheap  measure.  Observe,  also,  that  the  cost  of  it 
is  likely  to  vary  according  to  the  number  of  houses. 

Notes  on  the  cost  of  mosquito  reduction  have  just  been 
made.  For  Mauritius,  which  contains  705  square  miles  (1,924 
square  kilometres)  and  a  population  of  534  persons  to  i  square 
mile,  I  estimated  that  a  general  mosquito  reduction  in  inhabited 
areas,  especially  in  towns,  would  cost,  for  minor  works  alone,  the 
sum  of  ;^5,6oo  (83,910  rupees)  per  annum.  For  making  this 
estimate  I  relied  upon  figures  given  to  me  by  the  Medical 
Department,  who  suggested  the  number  of  workmen  which 
would  be  required  for  each  village,  plantation,  town  and  district, 
and  the  sum  includes  funds  for  the  director,  and  travelling 
expenses.  But  it  does  not  include  the  cost  of  the  major 
measures,  that  is,  the  drainage  of  large  marshes,  and  dealing 
with  such  waters  as  require  the  advice  of  an  engineer  (section 
35  (8)).  This  cost  was  estimated  in  Mauritius  by  the  Public 
Works  Department  at  a  capital  expenditure  of  about  ;^42,ooo 
(630,000  rupees),  but  I  advised  that  these  major  works  should 
be  undertaken  only  where  the  minor  works  might  be  found, 
after  experience,  to  be  ineffective. 

For  the  reasons  already  given  it  is  almost  impossible  to 
furnish  any  general  estimate  for  mosquito  reduction  anywhere. 


39]  COMPARISONS  307 

The  cost  depends  upon  the  number  of  major  works  required, 
the  price  of  labour,  the  price  of  expert  supervision,  the  local 
laws,  and  the  local  efficiency  of  administration.  It  is  very 
difficult  to  extricate  from  the  accounts  of  various  campaigns 
the  money  expended  on  mosquito  reduction  alone.  In  the 
town  of  Port  Said,  however,  where  there  is  very  little  rainfall 
and  where  a  complete  Culicine  reduction  has  been  carried  out, 
the  cost  has  been  about  5d.  per  head  of  population  per  annum 
(section  53). 

I  have  already  stated  that  mosquito  reduction  has  the  great 
advantage  that  it  can  be  carried  out  by  Government  alone  with- 
out reference  to  the  people.  Labourers  can  be  employed  to 
treat  Anopheline  waters  or  to  clear  away  Culicine  waters  from 
the  backyards  of  houses,  without  causing  any  real  trouble  to 
the  public.  It  is  not  necessary  for  Government  officials  to  go 
about  persuading  householders  to  do  this  or  that,  or  for  medi- 
cal men  to  examine  large  numbers  of  individuals,  and  so  on. 
On  the  other  hand,  mosquito  reduction  may  just  possibly  be 
essentially  unfeasible  in  places  where  the  breeding  waters  are 
such  that  they  cannot  be  removed  for  any  cost  that  can  be 
afforded  by  the  local  funds ;  and  this  is,  of  course,  a  question 
upon  which  it  is  impossible  to  make  general  statements. 

As  a  broad  rule  the  cost  of  mosquito  reduction  must  always 
tend  to  vary  according  to  the  area  of  the  country  treated.  [X 

It  is  often  thought,  especially  by  medical  men,  that  the 
cost  of  prevention  by  treatment  is  almost  nil.  We  write  pre- 
scriptions, which  cost  us  nothing  and  which  are  made  up  by  the 
dispenser  ;  and  we  often  seem  to  think  that  a  similar  prescrip- 
tion can  be  given,  at  the  same  small  cost,  to  a  whole  nation. 
But  the  cost  is  sure  to  be  very  considerable.  For  Mauritius 
in  addition  to  the  mosquito  reduction,  I  prescribed  a  very 
partial  scheme  of  prevention  by  treatment,  costing  30,cxx) 
rupees  for  the  quinine  alone,  3,600  rupees  for  its  preparation 
and  despatch,  and  6,000  rupees  for  the  services  of  five  quinine 
dispensers,  amounting  to  ;£'2,640,  or  39,600  rupees,  per  annum. 


3o8  PREVENTION  [Sect. 

This  was  without  the  salary  of  a  director  and  cost  of  office,  etc., 
and  it  was  proposed  that  the  quinine  should  be  distributed 
gratis,  but  chiefly  in  intensely  infected  localities. 

Here  again  the  cost  must  always  depend  largely  upon  the 
local  conditions.  A  highly  civilised  and  prosperous  people  will 
take  the  drug  readily,  where  a  very  ignorant,  poor,  coloured 
population  will  require  the  utmost  amount  of  persuasion.  Thus 
we  have  to  pay  not  only  for  the  amount  of  the  drug  used,  and 
for  its  preparation  and  despatch,  but  also  for  an  agency  which 
will  distribute  it  to  the  people  and  will  persuade  them  to  use 
it  properly.  We  are  very  apt  to  forget  this  last  and  very 
costly  item.  Think  for  a  moment  of  the  position  of  the  very 
poor  in  malarious  villages  and  towns.  The  occupant  of  each 
house  is  generally  obliged  to  go  to  his  labour  extremely  early 
in  the  morning.  His  wife  has  her  household  duties  and  her 
children  to  attend  to.  What  time  have  they  to  obtain  the  drug 
at  local  dispensaries  which  may  perhaps  be  miles  distant ;  and, 
very  often,  what  money  have  they  to  purchase  it  near  at  hand .? 
Moreover,  neither  the  man  nor  the  woman  has  time  to  force  the 
medicine  down  the  throats  of  the  younger  children.  The  same 
difficulties  recur  day  after  day  and  week  after  week,  perhaps 
during  the  whole  of  the  malaria  season,  and  even  beyond  it. 
Meanwhile  patients  rebel  against  the  medicine,  just  as  much  as 
those  who  care  for  them  rebel  against  the  necessity  of  fetching 
it,  and  soon  there  is  very  apt  to  be  a  general  rebellion.  This 
has  been  strongly  felt  already  in  many  localities,  where  pre- 
vention by  treatment  has  been  much  practised  ;  and  in  fact  it 
was  for  this  reason  that  my  advice  was  sought  both  at  Ismailia 
and  in  Mauritius.  Dr  Malcolm  Watson  has  also  made  some 
important  remarks  under  this  heading  (section  57). 

In  my  Mauritius  report  I  laid  down  that  for  most  tropical 
countries  the  only  effective  way  of  giving  quinine  is  {a)  to  give 
it  gratis,  {b)  to  give  sufficient  quantities  to  last  each  patient  for 
one  or  two  weeks  or  more,  and  {c)  to  distribute  it  actually  from 
house  to   house.      Now  all   this   must   cost   the   state   a  very 


39]  COMPARISONS  309 

considerable  sum.  As  a  matter  of  fact  a  large  number  of  fully- 
qualified  medical  men,  and  also  qualified  assistants,  must  be 
employed  to  carry  out  this  distribution  ;  and  we  must  remember 
that  the  salary  of  a  fully  qualified  medical  man  is  as  much  as 
the  wages  of  about  fifty  coolies  (at  least  in  India),  and  the 
salary  of  a  reliable  qualified  assistant  may  amount  to  as  much 
as  the  cost  of  five  to  ten  coolies. 

Regarding  the  feasibility,  independent  of  cost,  we  must 
again  remark  that  this  measure  does  not  accord  with  sanitary 
axioms  6  and  7. 

The  cost  will  tend  to  vary  according  to  niiniber  of  population. 
To  sum  up — protection  is  evidently  a  personal  or  domestic 
measure  which  cannot  be  forced  by  any  government  on  the 
people,  unless  the  former  is  willing  to  supply  the  nets  or  screens 
to  the  poor — the  cost  of  which  would  probably  largely  exceed 
that  of  mosquito  reduction,  at  least  in  towns.  But  protection 
should  always  be  adopted  for  public  buildings  and  isolated 
houses,  such  as  railway  stations,  rest-houses,  and  houses  on 
estates.  I  think  that  it  might  also  be  used,  even  at  the  cost 
of  supplying  netting,  for  villages  in  proximity  to  large  marshes 
which  cannot  be  drained  without  great  expense.  At  the 
same  time  it  should  always  be  urged  on  the  public  by  means 
of  lectures,  pamphlets  and  placards,  which  cost  Government 
almost  nothing,  and  certainly  have  a  good  effect. 

Practically,  therefore,  for  public  prophylaxis  we  are  called 
upon  to  choose  between  mosquito  reduction  and  quinine. 
Ideally  the  advantages  of  mosquito  reduction  are  simply  over- 
whelming—  so  much  so  that  I  urge  it  should  be  universally 
adopted  in  all  towns  i?i  the  tropics^  as  a  part  of  a  general  crusade 
against  vermin  of  every  description.  The  relief  caused  by 
removal  of  the  mosquito  pest  is  great  enough  to  compensate 
for  the  small  cost  involved  (in  towns)  even  if  the  insects  do 
not  carry  any  disease. 

Practically,  however,  our  choice  is  often  limited  by  the 
financial  position  of  the  place  and  time.     To  familiarise  him- 


3IO  PREVENTION  [Sect. 

self  with  the  question  the  reader  will  do  well  to  recall  to  his 
memory    various    localities    which    are    well    known    to    him. 
Suppose,   for   illustration,  that    malaria  were  to  break  out  in 
London  round  Hyde   Park  in   consequence  of  an  obstruction 
to   the    drainage   to   the   Serpentine    river.      Can    we   suppose 
for  a  moment  that  the  authorities  would  not  at  once  under- 
take   Anopheline    reduction    by    removing    this    obstruction  ? 
Would  not  this  be  much  cheaper  and  almost  infinitely  more 
convenient  than  to  force  people  to  screen  their  houses  or  to 
take  quinine,  while  the  hypothetical  mosquitos  are  allowed  to 
remain  as  numerous    as    before  ?     Precisely  the   same   answer 
must  be  given  in  the  case  of  most  cities,  towns  and  even  large 
villages  in  the  tropics.     But  now  take  another  extreme  case, 
and  suppose  that  the  disease  were  to  break   out  in  any  large 
rural  area  in   Europe,  such  as  among  the   bogs  and  lakelets 
of  Connemara.     What  practical  hygienist  would  urge  mosquito 
reduction   here,  with   the   immense   cost   involved,   merely   for 
the  benefit  of  a  few  scattered   farm  -  houses.     The  appropriate 
measures   would    obviously    be   protection    and    quinine,   as   a 
general  rule  ;  but  even  here,  we  might  occasionally  find  villages 
in   which  the  Anophelines  breed   in  a  few  local  waters  which 
can  be  removed  at  a  smaller  expense  than  would  be  involved 
in  the  other  measures.     In  fact,  between  the  two  extreme  cases 
suggested,  there  are  innumerable  instances  where  either  of  the 
measures  or  both  may  be  used,  and   where  the  director  must 
use  his  own  judgment. 

The  cost  of  reduction  of  Anophelines  tends  to  vary  with 
area,  and  not  with  population.  It  does  not  matter  much 
whether  the  area  is  crowded  with  houses  or  not ;  though,  if 
anything,  density  of  population,  necessitating  well  -  paved 
streets  and  the  removal  of  agriculture,  will  tend  to  cheapen 
the  cost  per  unit  of  area.  Thus  roughly,  the  cost  of  Anopheline 
reduction  for  a  square  mile  of  densely-crowded  city  or  town 
is  likely  to  be  actually  less  than  that  of  the  Anopheline  reduc- 
tion for  a  square  mile  of  uninhabited  wilderness.     In  the  former 


39]  COMPARISONS  311 

case  the  expense  will  benefit  a  large  number  of  human  beings, 
and  in  the  latter  case  only  the  birds  and  beasts. 

On  the  other  hand,  the  cost  of  case  reduction  and  quinine 
prophylaxis  must  vary  directly,  not  with  area,  but  with  popula- 
tion. It  will  be  vastly  greater  in  a  crowded  square  mile  than 
in  a  square  mile  containing  only  a  few  cottages.  Therefore 
evidently  mosquito  reduction  is  called  for  by  every  considera- 
tion in  the  case  of  crowded  areas,  and,  on  the  other  hand, 
quinine  tends  to  be  the  more  proper  ipeasure  amongst  a 
scattered  population,  where  Anopheline  reduction  would  be 
too  expensive  for  the  local  funds.  This  is,  of  course,  a  general 
rule,  exceptions  to  which  must  be  carefully  considered  by  the 
director  himself. 

Much  thoughtless  matter  has  been  written  on  this  point. 
For  instance,  it  has  been  stated  that  because  quinine  has  proved 
so  beneficial  in  Italy,  it  is  also  the  appropriate  measure  for  all 
malarious  countries.  But  the  success  of  quinine  there  does 
not  prove  that  mosquito  reduction  might  not  have  been  equally 
successful,  possibly  even  at  the  same  cost.  I  do  not  say  that 
this  is  the  case,  but  it  might  be  so.  Moreover,  the  conditions 
in  Italy  and  elsewhere  may  be  extremely  different.  Italy 
possesses  a  temperate  climate  which  admits  of  mosquito-breed- 
ing only  during  a  few  months  of  the  year,  so  that  there  is 
plenty  of  time  for  the  treatment  of  old  cases  during  the  non- 
malarious  months.  Italy  is  also  a  highly  civilised  country 
with  an  intelligent  white  population,  amongst  whom  there  are 
numbers  of  medical  men  who  speak  their  own  language,  and 
who  add  to  their  practice  by  the  treatment  of  cases  of  malaria. 
Lastly,  in  Italy  malaria  occurs  principally  in  rural  areas,  that 
is  just  where  quinine  is  rationally  called  for.  What  more 
natural  than  prevention  by  treatment  in  it.  But  in  many  other 
countries  the.se  conditions  do  not  obtain  ;  malaria  abounds  in 
towns ;  the  population  is  ignorant  and  often  stupid  ;  there  are 
very  few  qualified  medical  men ;  infections  occur  nearly  all 
the  year  round  ;  and  the  cost  of  maintaining  medical  men  and 


312  PREVENTION  [Sect. 

dispensers  for  quinine  distribution  may,  in  urban  areas,  far 
exceed  that,  not  only  of  Anopheline  reduction,  but  of  mosquito 
reduction  in  general.  We  really  must  not  apply  rules  suitable 
for  one  country  to  all  other  countries.  We  have  to  consider 
each  case  on  its  own  merits. 

Protection  is  a  measure  for  individuals,  mosquito  reduction 
for  local  governments  and  municipalities,  guided  by  their  sani- 
tary departments,  and  prevention  by  treatment  for  doctors.  It 
is  not  to  be  wondered  at  that  the  last  named  are  so  fond  of 
the  last  measure ;  they  are  acquainted  with  drug  giving,  but 
often  not  acquainted  with  public  health  matters,  drainage  and 
general  municipal  polity.  They  naturally  tend  to  select  quinine, 
and  often  very  wisely  so.  In  many  cases,  however,  it  would 
have  been  a  wiser  policy  to  have  adopted  the  larger  measure 
from  the  first. 

Up  to  the  present  we  have  considered  each  measure  separ- 
ately ;  but  in   many  cases,  probably  in  nearly  all,  it  may  be 
better   to   adopt  a   combination  of  several    measures  partially 
carried   out.       In   fact,  practically  it    nearly  always   comes  to 
this.     As  previously  stated,  the  complete  adoption  of  any  one 
measure    is   generally    impossible ;    we   cannot    remove   every 
mosquito,  nor  can    we  treat   every    case.      Possibly   a    partial 
mosquito   reduction    combined    with    a   partial    case   reduction 
will  produce  the  same  amount  of  malaria  reduction  at  much 
less  cost.     In  other  words,  we  remove   what  breeding  waters 
we  can  remove  without  great  expense,  and  we  treat  as  many 
of  the   infected    persons    as  possible.     At   the   same   time   we 
urge  protection  upon  the  populace  and  adopt  various  methods 
under  different  local  conditions.     The  proper  policy  is  not  the 
protection  policy,  nor  the    mosquito  reduction  policy,  nor  the 
quinine    policy,   but    an    opportunist    policy    which    uses   any 
weapon  it  can.     It   is  sometimes  stated  that  this  opportunist 
policy  will  cost  more  than  the  specialised  policy  ;  but  this  does 
not  follow  at  all.     Ultimately  we  have  to  frame  our  measures 
according  to  local  feasibility. 


4o]  FIRST   STEPS  313 

40.  Conduct  of  the  Campaign. —  Up  to  the  present  most  of 
the  anti-malaria  campaigns  have  been  due  to  the  intelHgence 
and  energy  of  individuals  ;  but  it  must  be  the  desire  of  all — 
and  certainly  this  book  has  been  written  in  the  hope  of  it — 
that  similar  work  should  now  be  attempted  in  every  civilised 
malarious  country.  This  has  not  hitherto  been  done,  because 
often  neither  governments  nor  health  departments  have  known 
how  to  commence  and  to  organise  their  efforts.  I  propose  now 
to  make  some  suggestions  on  the  point.  They  are  based  upon 
the  scheme  proposed  by  me  for  Mauritius,  after  careful  con- 
sultation with  the  capable  medical  profession  of  that  colony. 
They  are  tentative  suggestions,  and  alterations  of  detail  may 
be  required  under  other  conditions,  and  even  in  Mauritius ; 
but  I  hope  that,  with  such  alterations,  the  general  scheme  will 
prove  applicable  to  most  malarious  countries,  especially  in  the 
tropics. 

(i).  First  steps. — Whether  the  campaign  is  to  be  a  large  or 
a  small  one,  the  authorities  must  begin  by  educating  not  the 
public,  but  themselves,  regarding  the  simple  but  often  ignored 
axioms  of  section  38.  The  following  points  must  also  be 
remembered : — 

{a)  In  most  places  the  campaign  can  never  cease — the 
disease  can  seldom  be  extirpated  once  and  for  ever, 
until  civilisation  has  reached  a  much  higher  state. 
We  should  be  prepared  for  the  fact  that  malaria 
reduction  must  become  a  permanent  part  of  the 
general  sanitary  campaign. 
{J})  Unless  the  work  is  to  be  a  pretence  it  cannot  be 
attempted  without  expense.  Perhaps  the  ideals  of 
the  third  and  fourth  axioms  cannot  be  reached — but 
they  must  be  remembered.  Rarely  can  we  destroy 
so  redoubtable  an  enemy  without  some  goldshed. 
But  every  penny  spent  is  likely  to  save  pounds 
both  to  Government  and  to  the  public.  Moreover, 
though  the  war  may  never  cease,  the  cost  of  it  is 


314  PREVENTION  [Sect. 

likely  to   diminish   with   good    administration,  and 
especially  with  success. 

(c)  Public  instruction   must  always  be  given,  but,  except 

perhaps  in  very  civilised  states,  it  is  not  likely  to 
be  entirely  effective  by  itself.  The  individual  may 
take  quinine,  use  nets,  or  prevent  breeding  in  his 
premises,  but  he  cannot  force  his  neighbours  to  do 
so,  nor  can  he  clear  the  surrounding  country  or 
drain  the  marshes.  Only  the  better  educated  classes 
are  likely  to  attend  to  sanitary  advice.  The  great 
public  is  an  infant  for  which  everything  must  be 
done  by  the  nurse.  The  poor  are  too  poor,  the 
idle  too  idle,  the  busy  too  busy,  to  concern  them- 
selves much  with  sanitary  injunctions.  Neverthe- 
less, instruction  costs  the  state  little  and  may 
occasionally  reach  the  small  percentage  of  the  wise. 

(d)  Sanitation    is    a  form   of  war.     It    requires   not   only 

money  and    effort,    but   also   thought,   organisation 

and  discipline. 
(2).  Appointment  of  a  directory. — This  being  the  case  the 
first  thing  to  do  is  to  appoint  a  commandant.  For  a  small 
campaign  in  a  town  or  district,  the  proposer  of  it,  whether  he 
be  an  administrative,  sanitary  or  medical  officer,  had  better 
appoint  himself  (without  salary)  and  then  proceed  to  collect 
what  army  he  can  in  the  form  of  sanitary  inspectors,  medical 
assistants  and  even  policemen.  He  can  then  begin  to  ask  for 
funds.  But  this  is  personal  effort ;  and  for  larger  areas  Govern- 
ment should  appoint  a  special  officer  in  the  Sanitary  Department. 
His  pay  and  status  must  depend  upon  the  area  to  be  dealt 
with.  He  should  be  thoroughly  acquainted  with  the  subject 
and  also  with  general  sanitary  administration — a  medical  man, 
or  possibly  an  entomologist  or  engineer,  or  for  very  large  areas 
an  administrative  officer. 

For  entire  countries  I  advocate  the  construction  at  once  of 
a  Malaria  Bureau  as  part  of  the  general  Sanitary  Department — 


4o]  DIRECTORY  315 

that  is,  a  director  with  a  trained  "malariologist,"  an  entomologist, 
a  sanitary  engineer,  and  a  statistician  as  subordinates,  and  a 
suitable  office.  The  bureau  will  collect  information  and  co- 
ordinate efiforts  throughout  the  country,  will  carry  out  inspec- 
tions, give  advice,  examine  results,  and  publish  reports. 

Those  who  have  no  acquaintance  with  public  affairs  may 
think  that  this  is  an  extravagant  suggestion.  In  1904  I  mooted 
the  idea  for  India  through  the  Secretary  of  State.  In  that 
country  malaria  has  been  officially  estimated  to  cause  about 
1,000,000  deaths  annually.  Government  spends  enormous  sums 
on  plague,  which  has  a  smaller  mortality  and  much  smaller 
morbidity ;  but  a  mere  cipher  on  malaria.  My  suggestion  was 
not  accepted,  and  not  even  a  director  was  appointed.  Hence 
the  efforts  made  there  have  been,  in  my  opinion,  too  discon- 
tinuous for  success  (section  59),  and  much  of  the  money  spent 
has  possibly  been  wasted. 

The  head  of  the  Sanitary  Department  must  often  himself 
direct  the  anti-malaria  work.  He  will  do  well  to  begin  at  once 
by  collecting  a  permanent  special  staff.  This  will  cost  money  ; 
but  it  will  save  much  more  which  is  otherwise  likely  to  be 
wasted  on  inexperienced  efforts.  Public  work  is  permanently 
successful  only  if  directed  by  officials  who  are  permanently 
interested  in  its  success.  Local  enthusiasts  perform  great 
services  in  originating  campaigns,  but  they  alone  cannot 
maintain  them  for  ever. 

General  anti-malaria  work  is  now  sure  to  be  commenced  in 
most  civilised  countries,  and  it  is  high  time  that  governments 
should  prepare  for  this  by  providing  the  necessary  adminis- 
trative nucleus. 

(3).  Anti-malaria  Leagues,  under  the  presidency  of  high 
officials,  consisting  of  numbers  of  medical  men  and  influential 
persons,  with  a  central  office  and  local  branches,  should  be 
started  at  once — have  been,  in  fact,  already  started  in  many 
places.  They  serve  to  interest  the  public,  to  disarm  opposition, 
and  to  enlist  active  allies.     To  them  should   be  entrusted  the 


3i6  PREVENTION  [Sect. 

dissemination  of  information  regarding  the  disease  by  the  well- 
known  methods  of  placards,  pamphlets,  postcards  and  lectures. 
Personally,  I  think  it  wise  not  to  demand  a  general  subscription 
for  membership,  as  this  tends  to  limit  the  list,  but  to  ask  for 
donations  from  Government  and  wealthy  individuals  in  order 
to  pay  for  the  printing  and  other  small  expenses  of  the  League. 
Unfortunately,  there  is  a  distinct  danger  that  the  Government, 
as  soon  as  the  League  has  been  formed,  will  attempt  to  shift 
responsibility  on  to  it.  It  is  not  often  that  the  League  will  be 
able  to  do  the  whole  work.  Its  duty  lies  principally  in  arousing 
public  attention  as  regards  protective  measures  and  quinine. 
It  can  seldom  undertake  extensive  mosquito  reduction  or  much 
quinine  distribution.  Lastly,  as  soon  as  the  novelty  wears  off, 
the  efforts  of  the  League  may  tend  to  slacken. 

(4).  Legislation. — The  next  thing  required  is  to  reconsider 
the  local  Government  and  municipal  sanitary  regulations  in 
order  to  take  power  to  deal  with  mosquitos  and  other  details. 
This  is  largely  a  lawyer's  matter,  as  most  regulations  are  so 
framed  that  they  may  be  interpreted  in  various  ways.  The 
Government  will  do  well,  therefore,  to  call  together  a  committee 
to  consider  the  subject  thoroughly.  Certain  clauses  are  given 
as  examples  in  section  64.  It  is  easy  to  overrate  the  import- 
ance of  legislation  in  the  campaign.  The  experienced  health 
officer  depends  upon  it  as  little  as  possible ;  but  it  is,  never- 
theless, occasionally  useful  to  control  objectors  and  other  foolish 
people.  Thus,  in  Egypt  my  brothers  found  it  better  to  ignore 
such  persons  rather  than  waste  time  over  compulsion,  and  my 
experience  has  always  been  the  same.  The  trouble  and  expense 
of  bringing  recalcitrants  to  book  is  greater  than  what  is  incurred 
in  doing  the  work  by  departmental  agency.  The  wise  health 
officer  seeks  to  trouble  the  public  as  little  as  possible,  and  the 
amateur  one  as  much  as  possible.  Laws  protecting  indentured 
coolies  should  be  carefully  revised  in  the  same  sense,  though 
this  is  seldom  necessary.  All  this  costs  nothing,  but  requires 
considerable  time  to  effect  in  consequence  of  the  unavoidable  and 


4o]  THE    MALARIA   SURVEY  317 

often  unnecessary  discussions  which  arise.  I  apprehend  that 
these  discussions  will  now  become  shorter,  because  every  colony 
is  adopting  the  required  legislation.  See  especially  R.  Boyce's 
book  [1910]  and  sections  59  and  64. 

A  serious  difficulty  in  the  way  of  all  sanitary  improvement 
lies  in  the  inadequacy  of  punishment  often  given  by  legislators 
for  sanitary  contraventions.  These  are  too  small  to  be  deterrent. 
Endless  petitions  are  allowed  ;  and  the  time  of  the  Sanitary 
Department,  which  should  be  spent  on  useful  work,  is  used 
up  in  attending  courts  and  writing  up  cases — a  simple  waste 
of  public  funds.  This  is  not  freedom  but  licence.  It  is  a 
very  low  form  of  civilisation  in  which  individuals  are  allowed 
to  abuse  the  freedom  which  civilisation  has  given  them  by 
poisoning  or  infecting  their  neighbours.  If  those  who  make 
and  administer  the  laws  were  called  upon  to  sit  by  the  side 
of  dying  patients,  as  medical  men  too  often  are,  and  to  watch 
the  effects  of  the  bereavements  that  follow,  they  would  not  so 
often  treat  these  serious  offences  as  jests  or  as  petty  failings. 
The  success  of  the  work  at  Panama  has  been  largely  due  to 
the  stringent  discipline  exerted ;  and  the  public  themselves 
have  become  thankful  for  it.  Sanitary  discipline  is  like  that 
of  the  sick-room,  against  which  only  the  most  foolish  patient 
rebels — to  his  own  cost.  I  would,  therefore,  strongly  advise 
the  Government  which  determines  upon  a  general  war  against 
malaria  to  tighten  up  the  reins  in  this  matter. 

(5).  The  pj'eliminary  malaria  survey.  —  The  necessity  for 
repeated  measurements  of  malaria  is  quite  obvious.  Without 
them  we  cannot  {a)  make  any  estimate  of  the  expense  which 
might  theoretically  be  incurred  for  prevention  by  axioms  3 
and  4,  and  {b)  determine  the  exact  effect  of  the  measures  which 
are  taken.  Thus,  the  authorities  will  not  feel  the  necessity  for 
the  demands  made  on  them,  nor  the  value  of  the  work  done, 
and  the  whole  campaign  may  tend  to  collapse.  This  happened 
in  1899  in  Sierra  Leone,  where  the  authorities  disliked  a  malaria 
survey  because  they  feared  that  it  would  alarm  the  public. 


3i8  PREVENTION  [Sect. 

Hence,  while  the  League  is  being  formed,  the  Director  will 
do  well  to  spend  some  months  in  making  his  preliminary- 
measurements  according  to  the  principles  given  in  sections  31 
and  32.  Maps  being  obtained,  the  local  total  death-rates  for 
as  many  years  as  possible  should  be  carefully  scrutinised  and 
compared  with  the  attendances  for  malaria  at  hospitals  and  dis- 
pensaries— the  results  being  entered  in  the  maps  and  registers. 
This  will  cost  nothing,  but  will  yield  information  regarding 
both  local  distribution  and  general  prevalence  which  will  be 
invaluable  for  testing  the  success  of  future  measures. 

At  the  same  time  the  measures  proposed  in  next  sub-section 
to  be  adopted  in  schools,  including  registration  of  enlarged 
spleen,  should  be  commenced. 

It  is  now  also  advisable  to  make,  if  possible,  a  general 
"  spleen  census,"  That  this  can  be  done  on  a  large  scale  at 
little  expense  has  been  proved  in  Mauritius  and  Ceylon, 
where  31,022  and  92,258  children  respectively  were  examined 
(section  22).  Of  course,  the  work  cannot  be  done  entirely  by 
the  Director  himself.  Orders  should  be  issued  to  Government 
medical  officers  to  undertake  it,  each  for  his  own  district,  and 
the  help  of  all  medical  men,  of  trustworthy  assistants  and  dis- 
pensers, and  of  large  employers  of  labour  should  be  solicited. 
Travelling  expenses  must  occasionally  be  paid,  and  I  think 
that  fees  ought  to  be  allowed  under  certain  circumstances,  as 
the  gratuitous  services  of  medical  men  are  too  often  demanded 
as  it  is.  The  Director  should  set  the  example  by  examining  as 
many  children  as  possible,  and  he  must,  of  course,  register 
all  the  results. 

The  season  during  which  the  spleen  census  is  taken  is 
important.  In  the  middle  of  the  malaria  season  the  figures 
are  probably  very  variable ;  so  that  it  would  be  better  to  select 
a  time  before  or  after  that  season.  I  advise  between  one  and 
two  months  before  the  commencement  of  the  season,  or  a 
period  within  about  one  month  after  the  end  of  it  —  in  the 
hope  of  obtaining  the  minimum  and  maximum  spleen  indices 


y 


4o]  MEASURES    IN    SCHOOLS  319 

respectively.  In  fact,  for  the  first  year  I  advise  that  the  census 
be  taken  twice,  namely,  at  the  periods  mentioned.  Of  course, 
it  is  not  necessary  or  possible  that  all  the  children  should  be 
examined  on  the  same  day,  but  I  think  that  the  work  ought 
to  be  done  within  about  one  month. 

(6).  Measures  in  schools. — From  this  point  the  actual  campaign 
commences,  and  the  first  principle  requiring  attention  is  that 
the  cheapest  measures  should  first  be  set  in  train.  The  Director 
will  be  able  to  do  much  at  little  cost  with  various  public 
institutions  according  to  the  principles  laid  down  in  section  37. 

Schools,  if  they  exist,  furnish  an  admirable  opportunity  for 
large-scale  work.  In  most  countries  the  schools  are  either 
maintained  entirely  by  Government  or  are  given  what  are 
called  "grants  in  aid,"  or  at  least  licences.  This  enables 
Government  to  maintain  a  close  control  over  the  health  of  the 
children,  and  the  Director  to  use  the  schools  for  his  great 
purpose.  Two  uses  can  be  made  of  them,  {a)  by  the  treatment 
of  children  with  fever  or  enlarged  spleen,  and  {b)  for  the 
repeated  measurement  of  malaria.  Both  measures  are  especi- 
ally suitable  for  children  since  they  are  the  principal  homes 
of  the  parasites.     I  advise  as  follows : — 

(i).  That    every   school   be  visited    once   a   quarter   by   a 
suitable  medical  officer  (who  may,  if  necessary,  be 
paid  for  the  work). 
(2).  That  at  this  examination  the  medical  officer  shall  select 
all  children  with  enlarged  spleen,  or  with  fever  at 
the  time  of  his  visit,  and  should  enter  their  names 
in  a  register  kept  by  the  schoolmaster. 
(3).  That  at  the  same  time  the  medical  officer  shall  advise 
the  schoolmaster  as  to  the  treatment  to  be  given  to 
the  child  during  the  next  three  months. 
(4).  After  the  inspection  the  medical  officer  should  report 
to   the    Malaria    Director   the   number    of    children 
found   to   show   signs   of    malaria,   and    the    latter 
should  incorporate  the  facts  in  his  statistics. 


320  PREVENTION  [Sect. 

(5).  At    the    next    inspection    the   medical   officer    should 

observe  the  number  of  newly-infected  children  and 

those   who   have   become   cured,  and  should  again 

report  the  facts  to  the  Malaria  Director. 

(6).  The   schoolmaster   should   give   the   medicine   to   the 

children  as  ordered  by  the  medical  inspector. 
(7).  Quinine  may  also  be  advised  for  the  children  who  are 
not  suffering  from  fever  or  enlargement  of  the  spleen, 
but  no  compulsion  should  be  used  to  force  them  to 
take  it. 
(8).  The    Medical    Department   should    supply  quinine   in 
freshly-made  pills  or  tablets,  in  appropriate  doses, 
to  each  school.     This  may  be  done  gratuitously  for 
the  schools  of  the  poor,  but  I  think  that  payment 
should    be    demanded    in    some    cases.      Different 
doses  should  be  put  up  in  different  canisters,  and 
sweets  may  be  allowed  for  small  children. 
(9).  The  medical    inspector  may  stop  the  drug,  if  in  his 

opinion  it  disagrees  with  a  child. 
I  do  not  advise  here  as  to  the  amount  of  the  drug,  which 
I  think  had  better  be  left  to  the  medical  officer.  A  useful  plan 
is  for  the  schoolmaster  to  give  the  medicine  when  the  child 
first  comes  to  school  in  the  morning.  It  may  not  be  considered 
advisable  to  dose  the  children  every  day  during  the  whole  three 
months,  though  this  may  perhaps  be  done  at  certain  times. 
Perhaps  the  first  fortnight  of  each  month  ought  to  suffice,  at 
least  for  a  trial.  During  the  malaria  season  the  drug  may  be 
given  more  continuously,  and  during  the  non-malarious  season, 
less  so. 

(7).  Measures  on  estates,  factories,  etc. — There  are  generally 
large  numbers  of  children  in  connection  with  the  above,  and 
these  may  be  managed  in  exactly  the  same  manner  as  children 
in  schools.  Estates  often  have  their  own  medical  officers,  who 
should  be  directed  to  keep  the  registers,  to  give  the  quinine, 
and   to   report  every  quarter   to   the    Malaria   Director.      The 


4o]  MEASURES   ON    THE   ESTATES  321 

latter   will    thus   possess  an  excellent    standing  record  of  the 
state  of  health  upon  each  estate  or  factory. 

In  addition  to  this  adults  on  estates  and  factories  must  also 
be  continuously  treated  if  they  are  sick.  The  defect  has 
generally  been  that  they  are  given  doses  only  for  a  day  or  two, 
thus  necessitating  their  frequent  presence  at  the  dispensary, 
a  thing  which  causes  endless  trouble  both  to  dispensers  and  to 
patients.  It  is  much  better  to  give  sufficient  quinine  to  last 
for  a  week,  or  fortnight,  or  more,  according  to  section  36. 

Whether  quinine  should  be  used  for  prophylactic  purposes 
depends  upon  the  severity  of  the  local  endemicity,  the  possi- 
bility of  reducing  Anophelines,  and  the  judgment  of  the 
Director  (see  especially  section  57). 

Whether  quinine  is  to  be  supplied  gratis  to  plantations,  etc., 
depends  upon  the  local  labour  regulations. 

(8).  Other  quinine  distribution. — I  suggest  the  following 
steps  in  accordance  with  section  36 : — 

(i)  A  number  oi  quinine  dispensers,  who  are  duly  qualified 
dispensers,  should  be  appointed  under  the  Malaria 
Director. 

(2)  Each   dispenser  should   be  stationed   at   a  convenient 

centre  within  an  area  allotted  to  him,  and  should 
spend  the  whole  of  his  time  in  house-to-house 
distribution  of  quinine  to  those  who  he  thinks 
require  it. 

(3)  He  should  be  provided  with  a  small  portable  case,  to 

be  carried  by  himself,  containing  a  day's  supply  of 
quinine  in  the  form  of  pills  or  tablets,  put  up  in 
canisters  of  different  doses. 

(4)  He  should  be  provided  with  a  uniform,  or  at  least  an 

official  badge,  and  a  written  authority  stating  his 
duties. 

(5)  Every  day  he  should  visit  a  number  of  houses  allotted 

to  him, 

(6)  On   coming   to  a  house   he   should  offer  the   quinine 

X 


322  PREVENTION  [Sect. 

gratis  to  all  persons  who  suffer  from  fever  or 
enlargement  of  the  spleen.  He  must  not  demand 
nor  take  any  payment  whatever,  either  for  medicine 
or  for  his  advice. 

(7)  He  may  give  the  drug  to  any  person  who  demands  it, 

in  doses  sufficient  for  a  week  or  a  fortnight,  if  he 
thinks  that  that  person  is  infected  or  is  in  imminent 
danger  of  becoming  infected. 

(8)  He  may  also  examine  children  for  enlargement  of  the 

spleen,  if  permitted  to  do  so  by  the  occupiers  of  the 
houses,  and  shall  keep  a  record  of  the  number  in 
which  he  finds  this  symptom. 

(9)  The   quinine   dispensers   should  be  well  instructed    in 

their    duties,   and    in   a    knowledge    of   malaria   in 

general.     They  should  furnish  a  report  every  month 

to  the   Malaria  Director. 

(10)  The    Malaria   Director   will    be   well    advised  to  send 

these    men    most  frequently  to  the  most  intensely 

infected  areas,  and  utilise  them  also,  if  necessary, 

for  providing  vermifuges  and  sulphur  ointment  to 

the  very  poor.     The  cost  of  this  will  be  but  small 

and  the  advantage  great. 

In    addition    to   the   quinine   dispensers,   I    advised    in    my 

report  [1908]  that  a  change  should   be  made  as  regards  the 

distributing  of  quinine  to  out -door   patients  of  hospitals  and 

dispensaries.     It  is  quite  insufficient  to  give  patients  only  a  few 

doses  for  a  few  days.     Enough  should  be  given  for  a  fortnight 

or  more. 

In  Mauritius  we  found  that  one  dispenser  could  visit  200 
houses  a  week,  and  giveaway  about  3-3  lbs. (about  1,200 grammes) 
of  quinine  to  about  650  sick,  or  nearly  3  grammes  to  each. 

I  must  again  remark  that  to  be  really  useful  the  drug  must 
simply  be  poured  out  in  unlimited  quantities.  A  certain  amount 
may  be  sold,  but  stinginess  in  this  particular  tends  merely  to 
defeat   the   main   object   in   view.      Government  quinine  may 


4o]  MOUSTIQUIERS  323 

be  distinguished  by  a  certain  colour,  as  done  in  India ; 
authorities  should  guard  against  the  possibility  of  their  quinine 
being  subsequently  retailed  to  purchasers  or  even  exported  ; 
but  too  many  precautions  will  have  the  effect  only  of  ruining 
the  whole  scheme,  the  object  of  which  is  wide  distribution,  for 
the  sake  of  saving  a  few  pounds.  The  cost  of  collecting  money 
for  small  sales,  and  of  sending  in  reports  of  exact  amounts 
distributed,  really  exceeds  the  cost  of  wastage,  unless  this  is 
allowed  entirely  without  any  limit.  Government  must,  I  fear, 
face  a  certain  loss  from  leakage,  but  this  should  be  looked  upon 
as  an  unavoidable  part  of  the  general  cost  of  the  campaign. 

(9).  Appointment  and  instruction  of  vioustiquiers. — We  now 
turn  to  mosquito  reduction.  The  first  necessity,  an  absolute 
one,  is  for  the  Director  to  have  a  number  of  subordinates  well 
trained  in  a  knowledge  of  mosquitos.  In  Mauritius  we  called 
these  men  moustiquiers.  They  were  paid  about  25  rupees 
a  month,  and  were  mostly  of  Indian  extraction.  The  men 
should  be  carefully  selected  for  intelligence  and  reliability  by 
the  Director  himself,  and  should  be  formed  into  a  class  to  be 
trained  by  him  personally.  It  will  be  found  that  they  learn 
their  work  in  a  surprisingly  short  time,  and  generally  take 
great  interest  in  it.  Each  man  should  be  taught  how  to  catch 
adult  mosquitos,  and  how  to  find  larvae  in  all  possible  breeding- 
places  ;  also  how  to  fill  up  holes  in  trees  and  rocks,  and  to 
direct  the  gangs  of  workmen  required  for  clearing  pools  and 
streams,  etc.  The  appointment  should  be  made  with  a  view  to 
permanency,  with  a  scale  of  increasing  salaries,  and,  if  possible, 
with  a  promise  of  pension.  This  is  obviously  an  economical 
principle,  because  after  a  year  or  so  moustiquiers  become  highly 
experienced  in  their  work.  After  he  is  trained,  each  man 
should  be  allotted  a  given  district,  consisting  either  of  town 
or  of  village,  or  of  open  country,  according  to  the  judgment 
of  the  Director.  The  duties  of  the  moustiquiers  will  consist 
in  ascertaining  all  the  breeding-places  in  his  district,  in  guiding 
the   works   of  the   malaria   gangs,   and   in   making  occasional 


324 


PREVENTION  [Sect. 


reports  to  the  Director.  Oral  reports  generally  suffice.  It  may 
be  advisable  to  appoint  head  moustiquiers  to  superintend  larger 
areas.  Each  moustiquier  should  be  provided  with  a  white 
enamelled  pan  or  sieve  for  finding  larvae  in  water. 

These  men  are  essential  for  a  continued  campaign  against 
mosquitos.  They  are,  so  to  speak,  the  local  eyes  of  the  Director. 
Without  them  there  will  be  no  permanence  in  the  measures, 
because  directors  and  superintending  medical  officers  may 
change  from  time  to  time,  while  the  staff  of  moustiquiers  will 
be  permanent.  In  fact,  many  campaigns  have  failed  because 
this  fundamental  point  was  overlooked. 

The  number  of  moustiquiers  will  depend  upon  the  amount 
of  work  allotted  to  each.  I  suppose  that  one  man  can  super- 
intend quite  lo  square  miles  of  area,  except  in  crowded  towns. 
If  the  campaign  is  to  include  Culicine  reduction,  more  men 
will  be  required  for  towns. 

Moustiquiers  are  exposed  to  considerable  risk  of  infection. 
Care  must  be  taken  of  their  health,  and  they  must  be  provided 
with  bed-nets. 

The  Director  can  send  his  most  reliable  men  to  outlying 
stations  and  plantations  in  order  to  report  to  him  as  to  mosquito 
breeding  there,  and  also  in  order  to  instruct  managers,  head- 
men of  villages,  and  so  on — a  thing  which  he  cannot  always 
do  himself. 

(lo).  Malaria  gangs  for  minor  works. — The  moustiquiers  do 
not  do  manual  labour,  which  is  entrusted  to  workmen  of  the 
class  usually  employed  for  gardening  and  engineering  works. 
The  duty  of  these  workmen  should  be  to  train  small  pools, 
to  keep  street  gutters,  surface  drains,  roadside  ditches  and 
channels,  margins  of  ponds  and  streams  clear  of  weeds  and 
obstructions ;  to  carry  out  rough  canalisation  of  streams,  to 
deepen  or  "  back-up "  breeding  -  ponds ;  to  fill  or  oil  other 
waters ;  to  fill  holes  in  rocks  and  holes  in  trees ;  to  cut  under- 
growth ;  and  to  deal  with  house  waters  which  breed  Culicines 
(section  35). 


4o]  GANGS  AND   OFFICES  325 

From  our  experience  in  Mauritius  I  advised  that  the  work- 
men be  formed  into  gangs  of  about  three  or  four  men  each. 
One  of  the  men  should  be  appointed  the  headman  of  each 
gang,  with  extra  pay,  and  should  be  responsible  for  the  work 
of  the  gang.  This  extra  pay  is  an  inducement  for  the  work- 
men to  remain  in  such  employment,  which,  like  that  of 
moustiquiers,  requires  considerable  training  for  economical 
working ;  and  it  is  astonishing  how  much  trained  men  will 
do  in  a  given  time. 

It  is  impossible  to  state  how  many  gangs  will  be  required 
for  a  given  area.  This  will  depend  entirely  upon  the  local 
conditions.  In  Mauritius  I  thought  that  one  gang  could 
manage  about  4  square  miles  as  a  very  rough  average,  and 
the  cost  of  each  gang  was  about  50  rupees  (;^3'3)  a  month. 
The  gangs  are  to  be  superintended  by  the  moustiquiers, 
or  by  special  headmen  if  necessary ;  but  the  Director  must 
frequently  examine  the  work  done.  It  may  also  be  frequently 
feasible  to  put  the  gangs  under  enthusiastic  local  medical 
officers,  or  district  officers,  or  members  of  the  Anti-malaria 
League,  subject,  of  course,  to  the  final  authority  of  the 
Director. 

(11).  Local  offices.  —  All  this  organisation  —  dispensers, 
moustiquiers  and  malaria  gangs  —  will  require  a  number  of 
local  offices  where  the  men  can  be  given  instructions,  paid, 
supplied  with  medicines,  oil,  tools  and  impliments,  etc.  Generally, 
as  the  whole  organisation  is  under  the  Medical  Department,  it 
will  be  better  to  make  local  dispensaries  the  headquarters  of 
each  local  malaria  administration  ;  but,  of  course,  this  question 
depends  upon  conditions.  I  do  not  think  it  is  necessary  to 
appoint  a  special  clerk  at  each  dispensary.  Perhaps  the  sanitary 
inspector's  office  may  be  more  convenient  than  the  dispensary 
in  many  cases. 

(12).  Major  works.  —  Here  the  fundamental  principle  of 
35  (8),  namely,  that  of  minor  works  before  major  works ^  must 
always  be  remembered.     It  is  folly  to  commit  the  state  to  a 


326  PREVENTION  [Sect. 

large  expenditure  where  a  small  one  may  suffice.  At  the  same 
time  it  may  sometimes  be  more  economical  to  do  the  major 
work  at  once.  Hence,  at  an  early  stage  of  the  campaign,  the 
Director  should  obtain  rough  conjectural  estimates  of  the  cost 
of  all  major  works  that  may  be  required.  Exact  estimates 
can  only  be  obtained  from  the  Public  Works'  Department  at 
considerable  cost,  incurred  for  accurate  surveying  and  skilled 
advice ;  but  Government  will  generally  be  able  to  ask  its 
engineers  to  prepare  the  rough  estimates  by  mere  inspection 
of  the  localities  concerned.  These  rough  estimates  are  now 
borne  in  mind  by  the  Malaria  Director,  who  shapes  his  policy 
accordingly. 

Of  course,  major  works  will  generally  demand  not  only  a 
considerable  capital  outlay,  but  also  an  annual  expenditure 
for  maintenance.  Government  always  finds  a  considerable 
difficulty  in  obtaining  the  former  item,  which  may  require  loans 
and  the  consent  of  higher  authorities.  The  Director  should, 
therefore,  generally  not  make  such  demands  until  he  is  con- 
vinced by  the  unsuccessful  result  of  minor  works  during  several 
years  that  the  expenditure  is  absolutely  necessary ;  unless  he 
and  the  Public  Works'  Department  consider  that  money  will 
thereby  be  saved  in  the  end. 

The  important  question  as  to  who  is  to  pay  for  drainage 
of  marshes  on  private  property  often  arises  ;  and  I  was  asked 
in  Mauritius  to  advise  upon  the  point.  I  first  enquired  officially 
whether  owners  could  be  forced  by  law  to  drain  such  marshes, 
or  to  pay  for  the  drainage  of  them  by  Government,  especially 
in  view  of  the  fact  that  such  drainage  might  greatly  enhance 
the  value  of  their  property.  In  reply  I  was  informed  that  in 
the  opinion  of  the  Law  Officer,  marshes  could  not  be  held 
to  be  nuisances  in  the  statutory  sense  of  the  word  ;  and  that 
legislation  had  been  proposed  but  presented  many  difficulties. 
The  answer  seems  to  me  to  depend  upon  {a)  whether  the 
existence  of  the  marsh  is  or  is  not  the  fault  of  the  owner, 
and  {b)  whether  the  removal  of  it  would  or  would  not  benefit 


4o]  MAJOR   WORKS  327 

the  general  public  as  well  as  himself.  For  instance,  if  there 
is  in  existence  a  sufficient  and  practical  outfall  for  the  marsh, 
or  other  means  of  dealing  with  it  in  the  owner's  property,  but 
one  which  the  owner  neglects  to  use,  or  refuses  for  his  own 
profit  to  use ;  and  if  he  neglects  to  render  the  marsh  innocuous 
by  such  reasonable  minor  works  as  may  be  required  by  the 
Medical  Department ;  and  if  it  is  proved  that  the  marsh  is 
actually  causing  sickness,  or,  in  the  opinion  of  the  Medical 
Department,  is  likely  to  cause  sickness ;  then  I  think  that 
he  (the  owner)  may  be  forced  to  do  the  work.  As  a  matter 
of  fact  a  marsh  in  a  malarious  country  is  a  nuisance,  and  the 
fact  that  this  is  not  recognised  by  law  proves  only  the  inefficiency 
of  the  latter.  If  a  person  can  be  forced  to  remove  or  clean 
a  latrine,  he  ought  most  certainly  be  forced  to  remove  or 
discharge  a  marsh,  and  for  the  same  reason. 

On  the  other  hand,  if  the  owner  of  a  marsh  has  done  all 
reasonable  minor  works  to  render  it  innocuous ;  if  the  major 
work  is  beyond  his  means,  or  cannot  be  carried  out  on  his 
property  ;  and  if  the  marsh  is  not  causing  or  is  not  immedi- 
ately likely  to  cause  public  sickness,  then  I  doubt  whether 
he  can  fairly  be  forced  to  undertake  the  expense.  Each  case 
must  be  judged  on  its  merits ;  and  Government  will  often  feel 
it  more  fair  to  pay  at  least  a  part  of  the  expense.  At  the 
same  time,  legislation  to  compel  defaulting  owners  should 
certainly  be  passed. 

Precisely  similar  difficulties  often  occur  in  connection  with 
water-ways,  drains,  polluted  rivers,  and  especially  irrigation 
channels ;  and  I  think  they  may  generally  be  met  on  the 
same  principle. 

(13).  The  annual  malaria  report. — I  think  it  is  most  essential 
that  a  report  upon  the  work  done  should  be  submitted  to 
Government  every  year.  It  should  be  prepared  by  the  Malaria 
Director,  and  should  commence  with  a  detailed  statement  of 
the  measurement  of  malaria  for  previous  years  as  well  as  for 
the  year  under  review.     It  should  then  describe  the  measures 


328  PREVENTION  [Sect. 

taken,  the  number  of  men  employed,  and  the  cost ;  and  should 
conclude  with  remarks  upon  the  results  obtained. 

This  report  will  enable  Government  to  judge  whether  or 
not  value  is  being  received  for  the  money  spent.  Officials 
are  apt  to  dislike  the  trouble  incurred,  but  it  is  a  necessary 
one.  In  British  possessions,  one  often  finds  a  single  per- 
functory annual  report  on  medical  matters,  and  we  should 
compare  such  with  those  excellent  monthly  reports  issued 
by  the  Americans  for  the  Panama  Canal  Zone. 

(14).  Cost. — I  will  content  myself  by  giving  the  approximate 
estimate  which  I  prepared  for  Mauritius  [1908]. 

Items  Rs.  per  annum. 

1.  Salary  of  the  Malaria  Authority  ....  6,000 

2.  Salaries  of  5  Quinine  Dispensers  (say)        .         .  6,000 

3.  Salaries  of  15  Moustiquiers           ....  4,560 

4.  Salaries  of  109  gangs  (327  men)  ....  65,400 

5.  Cost  of  quinine  (say) 30,000 

6.  Preparation  and  despatch  of  quinine  (say)  .         .  3,600 

7.  Office  of  Malaria  Authority  (say)         .         .         .  1,500 

8.  Implements,  etc.,  for  gangs  (say  Rs.  50  a  gang) .  5,45© 

9.  Travelling  expenses  for  staff  (say)        .         .  2,000 
10.  Margin  for  possible  calls 10,490 


Total 


135,000 


This  amounts  to  ^9,000  per  annum  for  a  population  of 
375,400  (1906),  or  0-36  rupees  per  head  per  annum,  and  r2% 
of  the  total  revenue. 

The  estimate  was  an  "  outside  one."  The  number  of  gangs 
of  men  was  determined,  not  by  myself,  but  by  the  Medical 
Department,  and  many  suppose  that  it  is  considerably  in  excess 
of  the  actual  requirements.  In  fact,  I  have  since  heard  that 
the  whole  work  can  probably  be  done  at  much  less  cost  My 
whole  scheme  has,  however,  been  held  over  pending  the  final 
settlement  of  the  financial  position  of  the  Colony.  This  has 
only  just  been  effected  (1910),  and  I  hear  that  the  scheme 
will  now  be  proceeded  with. 

In  addition  to  the  above  annual  expenditure,  we  had  to 


4o]  COST  329 

consider  the  major  works.  A  rough  conjectural  estimate  for 
these  was  prepared  by  the  Public  Works  Department,  and  was 
put  at  630,000  rupees  for  capital  expenditure,  together  with 
42,300  rupees  for  annual  maintenance.  But,  as  I  have  said, 
I  hope  that  experience  will  prove  that  little  of  this  will  really 
be  called  up. 

Critics  of  my  report  have  complained  that  such  expenditure, 
though  it  may  be  possible  for  Mauritius,  will  be  altogether  too 
vast  for  other  countries.  The  total  revenue  of  Mauritius  is 
9,915,863  rupees,  of  which  749,827  was  allotted  to  the  Medical 
and  Health  Department  and  to  quarantine.  Hence  the  proposed 
malaria  expenditure  amounted  only  to  i"2//  of  the  total  revenue, 
and  to  18^  of  the  medical  and  sanitary  revenue;  while  the 
disease  causes  1/3  of  the  total  sickness,  and  costs  the  colony 
about  1,000,000  rupees  a  year  (section  32).  The  sum  of 
about  one- third  of  a  rupee  per  head  of  population  is  scarcely 
too  much  to  pay  for  all  the  advantages,  not  only  of  malaria 
reduction,  but  of  very  considerable  mosquito  reduction,  and 
general  "  cleaning  up." 

Moreover,  I  may  note  again  that  the  malaria  gangs  can  be 
largely  utilised  for  general  sanitary  purposes,  and  for  perform- 
ing many  useful  offices  during  the  non-malarial  season.  On 
the  whole  I  am  quite  convinced  that  this  expenditure  would 
be  a  very  small  one  for  any  population,  compared  with  the 
benefits  obtained. 

Of  course,  the  Malaria  Director  will  have  to  prepare  similar 
estimates  before  he  engages  large  numbers  of  men.  Unfortun- 
ately, it  is  always  impossible  to  state  without  trial  how  many 
gangs  are  required  for  a  given  area.  Thus,  the  Director  is 
almost  forced  to  commence  with  the  most  populous  areas,  and 
especially  with  the  most  malarious  ones.  He  must  point  out 
these  difficulties  to  the  Government,  and  must  do  the  best 
he  can. 

(15).  Remarks.  —  Amateurs  are  fond  of  advising  that  all 
practical   measures  should  be  postponed  pending  the  carrying 


330  PREVENTION  [Sect. 

out  of  detailed  researches  upon  the  habits  of  the  Anophelines, 
the  parasite  rate  of  localities,  the  effect  of  minor  works,  and 
so  on.  In  my  opinion  this  is  a  fundamental  mistake.  It  implies 
the  sacrifice  of  life  and  health  on  a  large  scale,  while  researches 
which  may  have  little  real  value,  and  which  may  be  continued 
indefinitely  are  being  attempted.  As  a  matter  of  fact,  the 
campaigns  at  Havana,  Panama,  Ismailia,  and  the  Federated 
Malay  States,  were  all  commenced  before  the  local  carriers 
were  definitely  incriminated  and  their  habits  studied.  We 
already  know  the  broad  general  principles  that  these  carriers 
breed  in  more  or  less  stagnant  waters,  and  that  protection  and 
prevention  by  treatment  are  valuable.  More  exact  knowledge 
of  the  habits  of  the  carriers  is  certainly  often  very  valuable, 
because  it  enables  us  to  deal  more  economically  with  them  ; 
but,  if  the  principle  of  minor  works  before  major  works  is 
remembered,  we  need  not  wait  for  the  full  development  of 
such  studies.  Moreover,  the  Medical  Director  will  be  able 
to  carry  out  such  researches  much  more  effectively  by  the 
aid  of  his  moustiquiers  and  quinine  dispensers  than  by  himself 
in  a  long  preliminary  survey  during  which  the  people  are 
allowed  to  continue  dying.  In  practical  life  we  observe  that 
the  best  practical  discoveries  are  obtained  during  the  execution 
of  practical  work,  and  that  long  academical  discussions  are 
apt  to  lead  to  nothing  but  academical  profit.  Action  and 
investigation  together  do  more  than  either  of  these  alone. 

I  strongly  advocate  a  generalised  campaign  in  preference 
to  one  which  deals  only  with  a  few  spots.  The  former  is  likely 
to  be  more  economical  in  the  end,  and  the  latter  is  more 
likely  to  dishearten  the  authorities  and  to  waste  money.  At 
the  same  time  financial  considerations  will  almost  always 
demand  stronger  efforts  in  the  larger,  more  populous,  and 
most  malarious  localities  —  at  least  to  begin  with.  But  the 
Director  must  always  hold  in  mind  and  prepare  for  extension 
to  every  part  of  his  domain. 

In   conclusion,    I    believe  that  anti  -  malaria   work   can   be 


4o]  REMARKS  331 

effected  for  little  cost  in  all  malarious  countries,  and  will  soon 
be  attempted  everywhere.  The  success  of  it  depends,  not  so 
much  on  profuse  expenditure,  as  on  the  intelligence,  enthusiasm 
and  energy  of  those  who  are  responsible  for  sanitary  affairs. 
He  who  undertakes  the  work  must  remember  that  he  is  a 
soldier  in  one  of  the  greatest  of  crusades,  which  has  for  its 
object  the  conquest  of  the  tropics  for  humanity. 


CHAPTER   VII 

SPECIAL   CONTRIBUTIONS 


By  Professor  L.  O.  HOWARD 

Chief  of  the  Bureau  of  Entomology,  Department  of  Agriculture^ 
Washington,  D.  C,  United  States 

41.  Anti-malaria  Work  in  the  United  States.— Beginning 
with  1900  and  gradually  increasing  in  amount  year  by  year, 
a  great  deal  of  anti-mosquito  work,  more  or  less  well  planned, 
has  been  done  in  different  parts  of  the  United  States  ;  but, 
looking  over  the  entire  field,  it  is  astonishing  to  note  how  little 
of  this  work  has  been  done  with  a  direct  sanitary  object  in 
view.  The  sanitary  point  has  been  held  constantly  in  mind 
in  the  operations  conducted  under  the  United  States  Govern- 
ment in  Cuba,  on  the  Isthmus  of  Panama,  in  Porto  Rico,  and 
in  the  Philippines,  but  in  the  United  States,  while  malaria  is 
prevalent  in  large  regions,  such  work  as  has  been  done  has 
been  instituted  for  the  most  part  with  the  sole  idea  of  relieving 
localities  from  the  nuisance  of  mosquitos,  thus  not  only  render- 
ing living  conditions  more  agreeable,  but  increasing  the  value 
of  real  estate.  In  fact,  one  of  the  best  bits  of  work  done  was 
accomplished  by  means  of  a  large  sum  of  money  presented  by 
a  wealthy  man  whose  object  was  not  primarily  the  improved 
health  of  the  people  of  the  region,  but  bettering  the  condition 
of  his  high-priced  race-horses,  which  were  suffering  from  the 
abundance  of  mosquitos.  Nevertheless,  what  anti  -  mosquito 
work  has  been  done  naturally  has  resulted  in  improved  con- 
ditions in  health  in  localities  included  within  the  scope  of 
operations. 

A    great  deal    of  valuable   drainage   work  has   been    done 
in  the  past  few  years  in  the  salt  marsh  region  of  the  North 

332 


Sect.  41]  LONG   ISLAND  333 

Atlantic  coast,  and  there  is  one  instance  of  this  upon  the  Pacific 
coast,  with  the  direct  idea  of  doing  away  with  the  salt  msCrsh 
mosquitos,  several  species  of  which  occur  in  such  localities, 
all  having  unusual  power  of  flight,  and  being  able  to  proceed 
inland  for  many  miles,  thus  annoying  the  inhabitants  of  a  large 
extent  of  country.  In  America  Anop/icles  mosquitos  are  rarely 
found  in  these  salt  marshes,  and,  in  fact,  there  is  but  one 
record  of  the  finding  of  Anopheles  larvae  in  such  locations  in 
the  United  States. 

One  of  the  first  operations  of  this  kind  was  conducted  by 
the  wealthy  owners  of  Center  Island,  off  the  north  coast 
of  Long  Island  in  Long  Island  Sound.  This  led  to  some- 
what elaborate  work  under  the  organisation  known  as  the 
North  Shore  Improvement  Association,  which  included  simple 
operations  over  a  considerable  distance  along  the  north  shore 
of  Long  Island,  and  in  the  vicinity  of  Oyster  Bay.  In  the 
course  of  this  work  the  breeding  -  places  of  Anopheles  were 
studied  and  mapped,  and  especial  effort  was  made  to  destroy 
them.  These  operations  took  place  in  1902  and  1903,  and 
have  been  reported  at  length  in  a  small  volume  published 
by  the  Association.  Later,  some  excellent  work  was  done  at 
Lawrence,  Long  Island,  which  demonstrated  the  feasibility  of 
controlling  the  salt  marsh  mosquitos  by  relatively  simple  and 
comparatively  inexpensive  ditching  operations.  These  opera- 
tions were  continued  for  four  years  at  an  annual  expense  of 
something  more  than  one  thousand  dollars  per  year. 

The  work  in  the  early  part  of  this  short  period  of  years 
was  usually  started  here  and  there  by  intelligent  and  up-to-date 
citizens,  citizens'  associations,  city  improvement  societies,  and 
women's  clubs.  The  California  work,  taken  up  in  1905,  was 
done  under  the  auspices  of  the  Burlingame  Improvement  Club. 
Excellent  anti-mosquito  work  was  begun  as  early  as  1900  on 
Staten  Island,  New  York,  by  the  Richmond  County  Club. 
Admirable  community  work  was  taken  up  during  1901  and 
1902  by  certain    New   Jersey   towns,  notably   South    Orange, 


334        ANTI-MALARIA  WORK  IN  THE  UNITED  STATES     [Sect. 

Elizabeth,  Montclair,  Monmouth  Beach  and  Summit,  and  a 
little  later  independent  work  was  begun  in  Greater  New  York 
under  Dr  Lederle,  which  included  the  mapping  of  all  mosquito 
breeding  -  places  within  the  city  limits.  Independently,  the 
health  officers  of  Brooklyn,  Jamaica  and  the  Brinx  began 
efficient  work,  while  the  summer  resorts  of  Arverne  and  Wood- 
mere  reduced  the  mosquito  supply  by  intelligent  operations. 
At  Willets  Point,  New  York,  intelligent  and  efficient  work 
was  carried  on  on  a  small  scale.  In  Massachusetts  interesting 
and  important  work  was  done  at  Brooklyn  and  at  Worcester. 

In  Brooklyn  the  Board  of  Health  first  considered  the  work 
in  August  1901,  and  in  September  all  the  breeding-places  of 
Anopheles  and  other  mosquitos  were  treated.  In  1902  all 
pools,  ponds,  ditches  and  other  breeding  -  places,  including 
catch-basins,  were  located  on  the  town  map,  the  approximate 
areas  were  determined,  and  the  number  of  catch  -  basins 
ascertained ;  breeding-places  of  Culex  and  A  nopkeles  respectively 
were  determined,  and  also  places  where  both  species  were 
breeding  together — this  being  done  in  order  to  ascertain  the 
proper  intervals  for  treatment  —  that  is,  whether  every  two 
weeks  or  every  three  weeks.  Public  dumps  and  other  places 
where  accidental  receptacles  of  water  might  be  found  were 
located  on  the  maps.  Light  fuel  oil  was  used  on  all  breeding- 
places. 

At  Worcester  the  work  was  of  the  most  interesting  kind. 
Dr  William  M'Kibben  and  Dr  C.  F.  Hodge  started  the  crusade. 
Breeding-places  were  mapped  and  photographed,  and  public 
lectures  were  given.  The  school  children  of  the  several  grades 
were  interested,  and  were  organised  into  searching  parties. 
Many  breeding-places  were  filled  up,  and  others  were  treated 
with  kerosene.  The  prevalence  of  malaria  in  Worcester  was 
pointed  out  by  those  engaged  in  the  crusade,  and  the  relation 
between  mosquito  breeding-places  and  the  houses  where  malaria 
patients  lived  was  shown.  A  map  was  prepared  showing  the 
exact   distribution   of  malaria    in    the   city,   and    photographs 


4i]  BALTIMORE  335 

were  made  showing  the  character  of  the  breeding  -  places  of 
the  malarial  mosquito.  It  is  probable  that  these  Worcester 
efforts  to  interest  the  school  children  were  the  first  made  in 
this  direction,  although  the  idea  was  carried  out  to  a  much 
greater  extent  later  in  San  Antonio,  Texas,  under  Dr  J.  S. 
Lankford. 

Other  early  work  was  carried  on  at  Pine  Orchard  and 
Ansonia,  Connecticut,  and  Old  Orchard  Beach  in  Maine,  and 
on  the  campus  of  the  Michigan  Agricultural  College  in 
Michigan.  At  Atlanta,  Georgia,  the  Sanitary  Department  used 
a  large  amount  of  kerosene  in  the  stagnant  pools  and  the 
swampy  places  around  the  city,  and  warned  the  citizens  to 
watch  their  rain  barrels  and  to  keep  their  gutters  open.  A 
great  many  pools  of  water  were  drained.  In  Savannah  some 
work  was  done,  and  the  number  of  mosquitos  was  reduced  very 
considerably.  At  Talladega,  Alabama,  under  the  direction  of 
Dr  B.  B.  Simms,  anti-mosquito  work  was  commenced  early  in 
1902,  and  carried  out  systematically.  St  Louis  took  up  the 
work  early  in  1903,  and  the  Municipal  Assembly  made  an 
appropriation  for  supplies.  The  Health  Department,  however, 
was  hampered  for  lack  of  men  and  little  work  was  done. 

Many  of  these  and  other  efforts  were  spasmodic  and  only 
temporary  in  their  effect ;  even  the  boards  of  health  in  some 
instances  lost  interest.  An  excellent  example  of  the  difficulties 
encountered  by  intelligent  citizens  was  shown  in  the  city  of 
Baltimore.  Intelligent  individuals  pointed  out  very  early  that 
a  large  part  of  the  mosquito  supply  of  the  city  could  be  easily 
handled,  and  year  after  year,  in  public  press  and  before  the 
Board  of  Health  and  the  City  Council,  these  persons  con- 
tinually agitated  the  subject  of  anti-mosquito  and  anti-malarial 
work.  Finally,  in  1907,  Mr  George  Stewart  Brown,  a  member 
of  the  City  Council,  succeeded  in  getting  an  appropriation  to 
start  the  work  for  that  year.  Much  of  this  money  was 
expended  in  extensive  advertising  in  the  street  cars,  etc.,  but 
the  remainder  was  expended  very  efficiently,  though  necessarily 


336      ANTI-MALARIA  WORK  IN  THE  UNITED  STATES    [Sect. 

with  only  partial  results,  by  organising  a  gang  of  men  to  drain 
and  fill  up  the  pools  in  the  vacant  lots  around  the  suburbs. 
Next  year  the  appropriation  was  reduced,  and  only  this  gang 
of  men  was  continued.  During  1909  no  appropriation  was 
made,  the  gang  of  men  was  dropped,  and  the  whole  question 
was  abandoned.  It  should  be  stated,  however,  that  before  the 
appropriation  was  made  an  ordinance  was  passed  by  the  City 
Council  requiring  every  householder  to  remove,  screen  with 
wire-netting,  or  keep  covered  with  oil  all  standing  water  around 
his  premises,  but  it  seems  that  no  real  attempt  was  ever  made 
to  enforce  this  ordinance.  Of  course  such  an  attempt  could 
hardly  be  successful  at  first  without  the  aid  of  an  especial 
appropriation  for  the  purpose,  and  at  the  present  time  the 
ordinance  seems  to  be  a  dead  letter. 

It  is  pleasing,  in  the  face  of  so  much  of  this  sort  of  thing, 
to  note  a  well-directed  and  rather  large-scale  bit  of  work  with 
a  direct  anti-malarial  bearing  which  was  begun  at  an  early  date, 
and  that  is  the  work  on  Staten  Island  under  Dr  A.  H.  Doty, 
the  health  officer  of  the  port  of  New  York. 

Staten  Island,  lying  in  New  York  Harbour,  had  had  a  rather 
unenviable  reputation  on  account  of  the  great  number  of 
mosquitos  present  and  the  continued  presence  of  malaria.  It 
was  largely  on  account  of  the  latter  condition  that  Dr  Doty 
began  his  investigation  in  1901.  He  soon  found  that  there 
were  two  factors  to  deal  with  in  this  work,  namely,  the  inland 
mosquitos  and  the  salt  marsh  mosquitos. 

In  the  extermination  of  the  inland  mosquitos,  the  section  of 
Staten  Island  which  was  known  to  contain  many  cases  of 
malaria  both  in  the  acute  and  chronic  forms  was  selected  for 
experimental  work.  This  section  consisted  of  a  basin  or  low- 
land about  a  mile  square,  containing  about  one  hundred  small 
dwelling-houses  some  distance  apart.  Within  its  boundaries 
were  a  large  number  of  stagnant  pools  varying  in  size  from 
ten  feet  in  diameter  to  an  acre  or  more  in  area.  A  house-to- 
house  visit  showed  that  at  least  20%  of  the  inhabitants  of  this 


4i]  STATEN    ISLAND  337 

district  were  suffering  with  some  form  of  malaria,  and  in  the 
immediate  vicinity  of  every  house  were  found  typical  breeding- 
places  in  the  shape  of  old  tinware,  rain-water  barrels,  cisterns, 
cesspools  and  ground  depressions,  many  of  which  contained 
larvae.  For  the  purpose  of  detecting  the  presence  of  adult 
Anopheles,  glass  tubes  fitted  with  cotton  plugs  were  distributed 
among  the  occupants  of  these  houses  with  the  request  that  the 
mosquitos  found  in  the  house  at  night  be  captured  and  placed 
in  the  tubes.  In  the  collection  were  found  many  Anopheles. 
These  were  particularly  numerous  in  tubes  coming  from  a  small 
group  of  houses.  In  one  of  the  latter  was  found  a  family  con- 
sisting of  five  persons,  all  of  whom  showed  the  acute  or  chronic 
form  of  malaria.  Dr  Doty  himself  secured  live  mosquitos  from 
the  interior  of  this  house.  On  the  first  evening  five  were 
captured,  and  all  but  one  were  Anopheles.  On  the  second 
evening  twenty-two  were  collected,  and  of  these  more  than  one 
\\2\{-w^xt.  Anopheles.  In  the  house  on  the  opposite  corner  was 
found  a  patient  suffering  from  an  acute  attack. 

In  the  beginning  considerable  difficulty  was  found  in  detect- 
ing the  breeding  -  places  of  the  Anopheles,  but  this  became 
easier  as  the  inspections  became  more  thorough.  For  instance, 
in  a  group  of  two  or  three  houses  close  together  a  number  of 
Anopheles  were  captured,  but  their  breeding  -  place  could  not 
be  found  for  some  time.  Finally,  in  the  backyard  of  one  of 
the  houses,  overgrown  with  weeds,  was  discovered  a  very  large 
metal  receptacle  filled  with  Anopheles  larvae,  and  with  many 
adults  in  the  immediate  vicinity.  This  receptacle  was  almost 
entirely  covered  by  underbrush. 

After  this  experience  the  men  employed  learned  to  make 
the  closest  possible  search,  and  to  find  probably  every  breeding- 
place. 

The  island  was  then  divided  into  small  districts,  which 
were  visited  by  mosquito  corps  consisting  of  five  men,  one  of 
whom  was  a  sanitary  police  officer  connected  with  the  New  York 
City  Department  of  Health.     The  equipment  of  the  mosquito 

Y 


338      ANTI-MALARIA  WORK  IN  THE  UNITED  STATES    [Sect. 

corps  consisted  of  a  large  waggon  provided  with  spades,  rakes, 
hoes,  scythes,  and  petroleum  oil.  A  house-to-house  inspection 
was  made  in  each  district.  House  owners  or  tenants  were 
required  to  remove  from  about  the  premises  all  receptacles 
which  might  act  as  breeding-places,  or  to  protect  them.  Rain- 
water barrels  and  cisterns  were  covered  with  wire-netting,  all 
roof  gutters  were  repaired,  and  pools  of  water  were  covered 
with  petroleum.  In  certain  instances  orders  were  sent  to  the 
owners  of  property  containing  depressions  in  the  soil  to  fill 
them  in  or  drain  them.  If  these  orders  could  not  be  enforced, 
the  mosquito  corps  returned  every  ten  days  or  two  weeks 
and  applied  more  petroleum.  Copies  of  a  circular  of  informa- 
tion were  delivered  so  far  as  possible  to  each  house  on  Staten 
Island  by  police  officers,  and  this  educational  campaign  brought 
about  valuable  co-operation  on  the  part  of  the  public. 

In  1905  the  details  of  this  work  were  presented  to  the 
Department  of  Health  of  the  city  of  New  York,  and  the 
city  government  granted  an  appropriation  for  the  drainage 
of  the  swamp  land  along  the  entire  coast  of  the  island.  With 
the  aid  of  this  appropriation,  ditching  was  carried  on  somewhat 
in  the  same  manner  in  which  it  has  been  carried  on  in  New 
Jersey.  Down  to  the  present  time  between  800  and  i,0CXD  miles 
of  ditches  have  been  dug.  The  swarms  of  mosquitos  soon 
practically  disappeared,  window  screens  were  discarded,  and 
meals  were  served  upon  the  verandas  of  the  hotels. 

With  the  malarial  and  other  inland  mosquitos  the  work 
was  carried  on  in  the  manner  above  described,  not  only  in 
the  built-up  portion  of  the  island,  but  also  in  the  open  spaces 
between  the  small  and  scattered  settlements.  During  the  past 
two  years  cases  of  malaria  on  Staten  Island  are  becoming 
practically  unknown,  and  for  the  past  year  Dr  Doty  has  been 
unable  to  secure  any  Anopheles,  whereas,  in  the  beginning  of 
the  investigation  they  were  found  almost  everywhere  on  the 
island.  The  statistics  of  the  Department  of  Health  indicate 
the  decrease  of  malaria  from   1905  on.     Prior  to  1905  malaria 


4i]  RESULTS    OF   DR   DOTY'S   WORK  339 

was  not  regularly  reported,  but  the  number  of  cases  was  surely 
very  much  greater  than  that  reported  in  that  year.  Since  1905, 
however,  they  are  stated  to  be  as  follows : — 1905,  thirty-three 
cases  ;  1906,  fifty-four  cases  ;  1907,  four  cases  ;  1908,  six  cases  ; 
1909,  five  cases. 

The  work  of  exterminating  malarial  mosquitos  has  been 
necessarily  slow,  as  the  area  involved  is  considerable,  the  island 
being  about  16  miles  long  and  4  to  6  miles  wide,  probably 
containing  over  eighty  thousand  inhabitants  in  large  areas 
between  the  various  towns. 

The  expense  of  the  operations  down  to  the  present  date 
has  been  about  $50,000 ;  this,  of  course,  includes  the  expense 
of  the  extensive  drainage  operations  in  the  salt  marshes.  Dr 
Doty,  in  addition  to  being  the  Health  Officer  of  the  Port  of 
New  York,  is  a  Commissioner  of  Health  of  New  York  City, 
and  he  carried  out  this  work  in  his  capacity  as  a  municipal 
officer,  and  not  as  a  State  official. 

Earlier  and  very  much  smaller  pieces  of  work  have 
previously  been  described  by  the  writer  in  "Mosquitos"  (New 
York,  1901),  including  the  work  done  by  Dr  W.  N.  Berkeley 
in  a  small  town  near  New  York  City  during  the  summer  of 
1900,  and  the  work  done  at  Chaptico,  Maryland,  by  the  Rev. 
William  Brayshaw,  in  both  of  these  cases  the  work  being 
directed  primarily  against  malaria.  Later,  some  excellent 
work  was  instituted  through  the  combined  action  of  the 
boards  of  health  of  Cambridge  and  Belmont,  Massachusetts, 
to  improve  the  sanitary  conditions  of  the  cities  of  Cambridge 
and  Somerville,  and  the  towns  of  Arlington  and  Belmont,  at 
the  inspiration  of  Mr  W.  L.  Underwood,  a  member  of  one 
of  the  boards  of  health.  This  was  effectively  carried  out  at 
an  expense  of  S600  without  assessment  upon  land-holders. 

In  1903  some  extensive  work  was  done  at  Newport,  Rhode 
Island,  at  the  expense  of  a  single  property  holder,  and  the 
following  year  the  Citizens'  Association  of  Flushing,  Long 
Island,  took  up  the  problem,    and  with  the  assistance  of  the 


340       ANTI-MALARIA  WORK  IN  THE  UNITED  STATES     [SECT. 

Board  of  Health  extensive  drainage  operations  have  been  carried 
on,  but  are  not  yet  completed. 

In  1903  the  American  Mosquito  Extermination  Society  was 
founded,  and  took  an  active  part  in  interesting  the  people  of 
the  United  States  in  the  mosquito  crusade.  It  was  founded 
for  the  purpose  of  educating  the  public,  of  bringing  about 
legislation,  and  of  securing  co-operation  and  exchange  of  ideas. 
It  held  its  first  anti-mosquito  convention  i6th  December  1903, 
and  continued  its  organisation,  publishing  several  bulletins, 
finally  disbanding  in  1907  in  consideration  of  the  fact  that  the 
objects  of  its  existence  would  be  taken  over  by  the  National 
Drainage  Association. 

In  1903  and  1904  work  against  mosquitos  was  undertaken 
by  the  state  entomologist  of  Connecticut,  Dr  W.  E.  Britton, 
who  made  careful  mosquito  surveys  over  the  whole  state,  and 
he  published  in  his  Annual  Report  for  1904  a  careful  and  well- 
illustrated  article  devoted  to  showing  how  the  mosquito  nuisance 
can  be  abated. 

The  largest-scale  work  taken  up  in  the  United  States,  how- 
ever, has  been  carried  on  by  the  state  of  New  Jersey,  and  this 
is  the  first  of  the  United  States  to  take  official  action  in  this 
direction.  This  work  was  instigated  by  Dr  John  B,  Smith, 
the  state  entomologist,  under  whose  direction  it  has  been 
carried  on,  and  resulted  largely  from  his  discovery  of  the  exact 
habits  of  the  salt  marsh  mosquitos.  An  admirable  state  law 
was  passed  carrying  a  very  considerable  appropriation.  The  law 
provided  for  a  survey  at  the  request  of  the  board  of  health  of 
any  city,  town  or  township,  which  should  map  all  mosquito 
breeding- places,  and  provided  that  the  board  of  health  must, 
after  the  survey,  proceed  to  abolish  the  breeding-places.  The 
law  provides  further  that  if  the  necessary  cost  of  the  work  shall 
equal  or  exceed  the  value  of  the  land  without  increasing  its 
taxable  value  the  board  may  apply  to  the  director  of  the  work, 
who  may,  if  he  deems  the  matter  of  sufficient  public  interest, 
contribute  from  the  state  funds  to  the  cost  of  the  necessary 


4i]  NEW  JERSEY  341 

work,  providing  that  not  more  than  50%  of  the  amount 
shall  be  contributed  in  any  case.  Under  this  appropriation 
and  during  the  past  three  years  much  admirable  work  has 
been  done  upon  the  salt  marshes  of  the  New  Jersey  coast.  In 
all  25,192  acres  of  marsh  land  have  been  reclaimed  by  3,633,974 
feet  of  ditching,  and  this  includes  a  shore  line  of  nearly  70 
miles.  Other  work  has  been  done  also,  more  specifically  against 
inland  mosquitos,  including  Anopheles. 

The  work  that  was  done  in  New  Orleans  during  the  yellow 
fever  outbreak  of  1905  was  an  object  lesson  to  the  people  of  the 
United  States.  This  work  was  so  thorough  that  it  resulted  in 
the  reduction  of  the  numbers  of  the  yellow  fever  mosquito  to 
a  minimum,  and  at  the  same  time  sensibly  decreased  the 
numbers  of  Anopheles.  This  work,  while  carried  on  originally 
under  the  United  States  Public  Health  and  Marine  Hospital 
Service,  has  been  continued  by  the  city  Board  of  Health,  and 
the  example  of  New  Orleans  in  this  direction  has  been  slowly 
followed  by  other  southern  cities. 

The  city  of  San  Antonio,  Texas,  has  the  honour  of  instituting 
and  carrying  forward  a  large-scale  effort  to  educate  the  children 
in  the  public  schools,  which  is  worthy  of  rather  specific  mention 
on  account  of  its  widespread  application. 

In  November  1903  there  were  a  few  cases  of  yellow  fever 
in  San  Antonio  which  caused  several  deaths,  and  an  inexcusable 
interruption  of  commerce  that  cost  hundreds  of  thousands  of 
dollars.  In  the  effort  to  allay  the  panic,  the  existence  of  yellow 
fever  was  denied,  not  only  by  persons  having  business  interests 
in  the  city,  but  by  many  medical  men  as  well.  Very  many 
adults  not  only  denied  the  existence  of  the  fever  in  the  city, 
but  denied  the  relation  between  the  mosquitos  and  the  fever. 
Perhaps  the  majority  of  the  adults  seemed  too  old  to  learn ; 
and  to  the  enlightened  physicians  it  appeared  that  it  was 
impossible  to  begin  education  at  the  wrong  end  of  life. 

The  Chairman  of  the  Sanitary  Committee  of  the  School 
Board  (Dr  J.  S.  Lankford)  grasped  the  happy  idea  that  if  the 


342       ANTI-MALARIA  WORK  IN  THE  UNITED  STATES    [Sect. 

children  were  properly  educated,  sanitary  matters  in  the  future 
would  be  much  better  attended  to.  He  suggested  to  the  Board 
that  it  would  be  valuable  to  educate  all  of  the  school  children 
of  the  city  in  prophylaxis  and  make  sanitarians  out  of  them  all. 
The  School  Board  heartily  approved  of  the  proposition,  and  the 
campaign  was  at  once  begun  to  educate  the  children  on  the 
subject  of  Insects  as  Disease  Carriers.  The  best  recent  medical 
literature  on  the  subject  was  procured  and  furnished  to  the 
teachers,  and  a  circular  letter  was  sent  to  them  outlining  a 
proposed  course  and  offering  a  cash  prize  for  the  best  model 
lesson  on  the  subject.  Teachers  became  deeply  interested  in 
the  subject.  A  crude  aquarium,  with  eggs  and  wrigglers, 
was  kept  in  every  schoolroom,  where  the  pupils  could  watch 
them  develop  ;  and  large  magnifying  glasses  were  furnished  in 
order  that  they  might  study  to  better  advantage.  The  children 
were  encouraged  to  make  drawings  on  the  blackboard  of 
mosquitos  in  all  stages  of  development ;  lessons  were  given  and 
compositions  were  written  on  the  subject.  Competitive  ex- 
aminations were  held,  and  groups  of  boys  and  girls  were  sent 
out  with  the  teachers  on  searching  expeditions  to  find  the 
breeding-places.  Rivalry  sprung  up  between  the  10,000  public 
school  children  of  the  city  in  the  matter  of  finding  and  reporting 
to  the  Health  Office  the  greatest  number  of  breeding-places 
found  and  breeding-places  destroyed.  Record  was  kept  on  the 
blackboards  in  the  schools  for  information  as  to  the  progress 
of  the  competition,  and  great  enthusiasm  was  stirred  up.  In 
addition  to  these  measures,  a  course  of  stereopticon  lectures 
was  arranged,  grouping  the  pupils  in  audiences  of  about  one 
thousand  from  the  high  school  down,  and,  in  Dr  Lankford's 
words,  "  It  was  an  inspiring  sight  to  watch  these  audiences  of  a 
thousand  children,  thoughtful,  still  as  death,  and  staring  with 
wide-open  eyes  at  the  wonders  revealed  by  a  microscope.  It 
seemed  to  me  that  in  bringing  this  great  question  of  preventive 
medicine  before  public  school  children  we  had  hit  upon  a  power 
for  good  that  could  scarcely  be  over-estimated."     The  result  of 


4i]  COST   OF    MALARIA  343 

this  work,  it  is  pleasing  to  say,  was  a  decided  diminution  in 
the  number  of  mosquitos  in  San  Antonio.  There  was  some 
opposition  among  the  people,  but  the  movement  on  the  whole 
was  very  popular.  One  result  of  this  work  was  that  while 
there  had  previously  been  from  fifty  to  sixty  deaths  a  year  from 
malarial  trouble,  the  mortality  was  reduced  75^  the  first  year 
after  this  work  was  begun,  and  in  the  second  year  it  was  entirely 
eliminated  from  the  mortality  records  of  San  Antonio. 

In  organising  community  work  against  mosquitos,  the 
school  children  hereafter  must  be  counted  upon  as  most 
important  factors.  Almost  every  child  is  a  born  naturalist, 
and  interest  in  such  things  comes  to  them  more  readily  than 
anything  else  outside  of  the  necessities  of  life.  They  are 
quick-witted,  wonderfully  quick-sighted,  and  as  finders-out  of 
breeding-places  they  cannot  be  approached  except  by  adults 
of  the  most  especial  training.  One  of  the  first  steps  that  a 
community  should  take  is,  therefore,  the  encouragement  of  the 
interest  of  the  children  in  the  public  schools. 

I  fear  that  it  will  appear  from  what  precedes  that,  consider- 
ing the  economic  loss  existing  in  the  United  States  through 
malaria,  which  has  been  estimated  by  the  writer  at  surely  not 
less  than  S  100,000,000  per  year  (see  Bulletin  No.  78,  Bureau 
of  Entomology,  United  States  Department  of  Agriculture), 
nothing  like  the  competent  work  has  been  done  that  should 
be  done,  or  really  that  should  have  been  done  in  the  past 
eight  years,  within  the  territorial  limits  of  the  United  States 
themselves.  While  very  many  sections  of  the  country  that 
were  originally  extremely  malarious  have  been  practically  freed 
from  malaria  by  the  drainage  of  swamp  areas,  undertaken  not 
as  a  measure  of  sanitation  but  in  order  to  add  to  the  supply 
of  arable  land,  it  is  nevertheless  seen  that  the  conditions  of 
improved  civilisation  have  brought  about  steadily  increased 
opportunities  for  Anopheles  to  breed,  and  this  increase  in  the 
number  of  breeding  -  places  and  kinds  of  breeding  -  places  is 
constantly  growing.     The  introduction  of  irrigation  into  many 


344      ANTI-MALARIA  WORK  IN  THE  UNITED  STATES    [Sect. 

portions  of  the  western  country  has  resulted  in  the  introduction 
of  malaria,  and  these  operations  are  going  on  with  a  very 
rapid  increment.  Moreover,  in  regions  which  are  not  dry  and 
which  need  no  irrigation,  the  construction  of  mill-dams,  the 
excavation  of  stone  quarries,  the  building  of  railroad  embank- 
ments and  many  other  operations  which  follow  rapidly  increas- 
ing populations  have  resulted  in  the  multiplication  ol  Anopheles, 
and  in  many  instances  the  introduction  of  malaria  has  been 
followed  by  its  rapid  spread  through  extended  regions.  On 
the  whole,  under  such  conditions  it  would  not  be  surprising  if 
malaria  were  increasing  rather  than  decreasing  in  the  United 
States,  and  the  mosquito  crusade  is  bound  to  become  an 
extremely  important  matter  within  the  next  few  years. 


References  on  Anti-malarial  Work  in  the  United  States. 

American  Mosquito  Extermination  Society.     Mosquito  Brief.     1904. 

American  Mosquito  Extermination  Society.  Bulletins  1-2,  1904 -1906. 
{Bulletin  i  is  issued  by  the  National  Mosquito  Extermination 
Society.) 

American  Mosquito  Extermination  Society.  Yearbook  for  1903- 1905,  con- 
taining the  proceedings  of  the  ist  and  2nd  anti-mosquito  convention. 
Edited  by  Henry  Clay  Weeks  and  Edward  Hagaman  Hall.  New 
York,  1 904- 1 906. 

Britton,  W.  E.  &  H.  L.  Viereck. — Report  on  mosquito  investigations. 
(Fourth  report  of  the  State  entomologist  of  Connecticut  Agr.  Coll.  Exp. 
Station  for  the  year  1904,  pp.  253-310,  pi.  X.-XVII.) 

Chase,  H.  Lincoln  &  J.  Albert  C.  Nyhen.—"  Abatement  of  the  Mosquito 
Nuisance  in  Brooklyn."  (Reprint  from  the  Journal  of  the  Mass.  Assoc, 
of  Boards  of  Health,  Boston,  1902- 1903,  vol.  xii.  pp.  190-203,  Jan.  1903. 
Reprint  is  14  pages.) 

Doty,  Alvah  H.  — "The  Mosquito:  Its  Relation  to  Disease  and  Its 
Extermination."  New  York,  1908.  26pp.  (Reprinted  from  the  New 
York  State  Journal  of  Medicine,  May  1908.) 

Doty,  A.  H.— "On  the  Extermination  of  the  Mosquito."  New  York,  1906. 
lopp.     (From  the  American  Journal  of  the  Medical  Scietices,  Feb.  1906.) 


4i]  REFERENCES  345 

Doty,  A.  H. — "  The  Use  of  Sulphate  of  Copper  alone,  and  its  Combination 
with  Lime,  for  the  Destruction  of  Mosquito  Larvae,  as  a  Deodorant,  and 
as  a  Disinfectant."  New  York,  William  Wood  &  Co.,  1905.  12pp. 
(Reprint  from  the  Medical  Record^  21st  Jan.  1905.) 

Howard,  L.  O. — "Economic  Loss  to  the  People  of  the  United  States 
through  Insects  that  carry  Disease."  Washington,  1909.  40pp.  (U.S. 
Dept.  of  Agr.  Bureau  of  Entomology,  Bulletin  No.  78.) 

Howard,  L.  O. — "  Mosquitos  :  how  they  live  ;  how  they  carry  disease  ; 
how  they  are  classified  ;  how  they  may  be  destroyed."  New  York, 
M'Clure,  Phillips  &  Co.,  1901.     xv.  241pp. 

Lankford,  J.  S. — "  Public  School  Children  and  Preventive  Medicine." 
New  York,  1904.  9pp.  (Reprinted  from  the  New  York  Medical  Journal 
for  loth  Dec.  1904.) 

M'KiBBEN,  William  W.  —  "Malaria  and  Mosquitos  of  Worcester.  A 
Year's  Observations  on  the  Habits  of  Culex  and  Anopheles."  Boston, 
1903.  9pp.  (Reprinted  from  the  Boston  Medical  and  Surgical  Journal^ 
vol.  cxlix.  No.  25,  pp.  665-669,  17th  Dec.  1903,  and  No.  26,  pp.  704- 
708,  24th  Dec.  1903.) 

North  Shore  Improvement  Association.  Reports  on  plans  for  the  extermi- 
nation of  mosquitos  on  the  north  shore  of  Long  Island  between 
Hempstead  Harbour  and  Cold  Spring  Harbour.  New  York,  1902. 
124pp. 

North  Shore  Improvement  Association.  Report  of  the  Association's  experts, 
Frank  E.  Lutz  and  William  W.  Chambers,  upon  the  work  of  mosquito 
extermination  during  the  summer  of  1902.     New  York,  1902.     26pp. 

QUAYLE,  H.  J. — "Mosquito  Control."  (Univ.  of  California,  College  of  Agr. 
Agr.  Exp.  Station,  Bulletin  No.  178,  1906.) 

Smith,  John  B. — Report  of  the  New  Jersey  State  Agricultural  Experiment 
Station  upon  the  mosquitos  occurring  within  the  state,  their  habits, 
life  history,  etc.     Trenton,  1904.     482pp. 

Smith,  John  B. — Report  on  mosquito  investigations.  (In  Reports  of  the 
Entomological  Department,  New  Jersey  Agri.  Coll.  Exp.  Station, 
for  the  years  1902- 1908.) 


By  Colonel  W.  C.  GORGAS,  United  States  Army 

Chief  Sanitary  Officer,  Isthmian  Canal  Commission,  Panama 

42.  Malaria  Prevention  on  the  Isthmus  of   Panama.— 

The  Panama  Canal  extends  diagonally  across  the  Isthmus  of 
Panama  from  south-east  to  north-west,  a  distance  of  42  miles 
from  shore  to  shore. 

Commencing  on  the  South  Sea  at  Panama  it  runs  up  the 
valley  of  the  Rio  Grande  river  to  Pedro  Miguel,  then  across 
the  divide  to  Bas  Obispo,  and  from  there  down  the  valley  of 
the  Chagres  to  Colon.  Roughly,  about  two  -  thirds  of  this 
distance  is  broken  and  mountainous,  and  one  -  third  low  and 
swampy.  About  one  -  fourth  of  the  population  lives  in  the 
lowlands  and  three-fourths  in  the  highlands. 

Before  coming  to  Panama  in  1904  the  Army  Medical  Corps 
had  had  very  little  experience  in  dealing  with  malaria  on  a 
large  scale  in  rural  districts.  The  mosquito  work  established 
by  the  Army  medical  officers  in  the  city  of  Havana  in  1901 
had  not  only  gotten  rid  of  yellow  fever  but  also  of  malaria. 
This  work  has  now  been  going  on  in  Havana  for  the  past 
eight  years,  part  of  the  time  under  Army  medical  officers, 
and  part  of  the  time  under  Cuban  officers,  and  is  the  most 
successful  example  of  municipal  malarial  work  that  I  know  of 

The  following  table  shows  the  decrease  of  malaria  under  these 

measures,  and  at  the  present  time,  its  practical  extinction : — 

1890   1891    1892    1893    1894    1895    1896    1897    1898    1899 
170    203    202    240    201    207    450    811    910    909 

Mosquito  work  commenced  February  of  this  year,  1901. 

1900     1901     1902    1903     1904     1905     1906     1907     1908     1909  (to  July) 
325      151       87       51         44       32        26       23        19         2 


Sect.  42]  DRAINAGE  347 

Ronald  Ross's  work  at  Ismailia  was  the  only  example  at 
this  time  that  I  knew  of,  pertaining  to  successful  anti-malaria 
work  in  rural  districts. 

At  Panama  our  anti  -  malarial  work  is  principally  rural, 
located  for  47  miles  along  the  line  of  the  railroad  between 
Panama  and  Colon.  The  railroad  in  general  follows  the  line 
of  the  canal.  In  this  distance  we  have  a  population  of  about 
eighty  thousand  living  within  a  half  a  mile  of  the  railroad, 
and  occupying  some  thirty  villages  and  camps,  and  more  or 
less  isolated  houses  scattered  between. 

In  this  article  I  shall  describe  the  sanitary  organisation  as 
it  existed  in  July  1908. 

This  strip  of  47  miles  along  the  railroad  is  divided  into 
eighteen  districts,  each  district  in  charge  of  an  inspector.  The 
inspector's  duties  consist  in  the  carrying  out  of  the  sanitary 
work  of  the  district,  and  for  this  purpose  he  had  at  his  disposal, 
on  an  average,  about  fifty  men.  The  anti-malarial  work  con- 
sists in  the  order  of  its  importance,  of: — 

(i).  Drainage, 

(2).  Brush  and  grass  cutting. 

(3).  Oiling. 

(4).  Use  of  larvicide. 

(5).  Prophylactic  quinine. 

(6).  Screening. 

(7).  Killing  mosquitos  in  quarters. 
Drainage. — He  is  required  to  drain  and  do  away  with 
all  pools  within,  approximately,  200  yards  of  all  villages,  and 
100  yards  of  all  individual  houses.  For  this  purpose  we  con- 
sider subsoil-drainage  by  far  the  most  effective  and  economical  ; 
second,  open  concrete  ditches  ;   and,  third,  open  ditches. 

The    porous    subsoil    pipes    give    a    perfect   anti  -  malarial 

drainage.     Besides  doing  away  with  all  breeding-places,  they 

enable  you  to  use  a  horse  -  mower  on  the  ground  so  drained, 

and  thus  much  cheapen  the  cost  of  subsequent  grass  cutting. 

We    use    the    open     concrete    ditch    in    localities    where 


348     MALARIA  PREVENTION  ON  ISTHMUS  OF  PANAMA  [Sect. 

subsoil  drainage  is  not  practicable,  such  as  flat  places  where 
the  fall  is  not  sufficient,  and  small  natural  rills  where  the  volume 
of  water  is  too  large  for  subsoil  drainage,  etc. 

The  objection  to  this  style  of  ditch  as  compared  with  the 
subsoil  is  that  it  requires  supervision  for  the  purpose  of  keeping 
it  free.  Any  obstacle  in  the  ditch  will  make  a  small  collection 
of  water,  which  in  this  warm  climate  will  breed  mosquitos  at 
any  time  of  the  year. 

Open  ditches  we  only  use  when  the  occupancy  is  going 
to  be  temporary,  not  more  than  two  years.  While  the  first 
cost  is  smaller  than  in  either  of  the  other  class  of  ditches,  the 
ultimate  cost  is  very  large.  In  a  locality  such  as  Panama, 
vegetation  grows  so  rapidly  that  the  ditches  have  to  be  cleared 
out  at  least  once  a  month,  and  when  clean  they  will  breed 
larvae  unless  treated  with  larvicide. 

We  pay  our  inspectors  from  one  hundred  and  twenty-five 
dollars  per  month  to  one  hundred  and  seventy-five,  and  thus 
get,  in  general,  an  educated  intelligent  class  of  men.  We  have 
attached  to  the  department  an  inspector  of  sufficient  engineering 
education  to  lay  out  the  ditches,  but  the  local  inspector  is 
entirely  responsible  for  their  execution.  In  general,  it  is  the 
character  of  work  such  as  the  farmer  does  through  our  country, 
and  any  man  of  ordinary  intelligence  is  capable  of  carrying  it 
out.  But  for  its  anti-malarial  success  it  is  important  that  the 
man  in  charge  should  have  a  good  knowledge  of  the  breeding 
habits  of  the  species  of  mosquitos  in  his  neighbourhood. 

Brush  and  grass  cutting. — The  inspector  is  required  to  keep 
the  tropical  undergrowth  cut  off  within  200  yards  of  villages 
and  100  yards  of  isolated  houses.  Within  this  area  the  grass 
must  be  kept  less  than  a  foot  high.  I  consider  this  scarcely 
less  important  than  drainage.  Brush  and  grass  shelter  the 
adult  mosquito,  and  they  will  reach  a  habitation  from  distant 
breeding-places  by  short  flight,  if  they  have  the  continuous 
protection  of  brush,  whereas  the  Anopheles  will  not  cross 
a  cleared  area  of  100  yards. 


42]  OTHER   MEASURES  349 

Oiling. — We  use  oil  where  drainage  is  either  impracticable 
or  too  costly,  such  as  the  edges  of  swamps,  edges  of  streams, 
etc.  In  a  large  construction  work  such  as  this,  temporary 
pools  are  constantly  being  formed.  The  oil  should  be  of 
such  consistency  that  it  will  spread  readily,  but  not  so  thin 
that  it  will  evaporate  too  rapidly.  For  this  purpose  we  use 
crude  oil  thinned  with  larvicide. 

Larvicide. — There  are  many  places,  such  as  the  grassy 
edge  of  ponds,  or  of  streams,  in  which  the  Anopheles  larvae 
love  to  breed,  and  where  oil  will  not  spread.  In  such  places 
we  use  a  poison  which  mixes  in  the  water  and  which  we 
denominate  larvicide.  We  have  done  a  good  deal  of  experi- 
menting to  get  an  effective  and,  at  the  same  time,  cheap 
larvicide.  Mr  Le  Prince  gives  the  formula  in  his  paper.  We 
use  per  year  about  4,500  barrels  of  oil  and  about  1,900  barrels 
of  larvicide. 

Prophylactic  quinine. — We  consider  quinine  taken  for  pro- 
phylactic purposes  an  exceedingly  important  measure  against 
malaria.  Quinine  is  given  gratis  to  any  one  applying  to  any 
one  of  our  dispensaries.  We  have  at  various  points  along  the 
line  21  dispensaries.  It  is  placed  on  all  hotel  and  mess  tables. 
But  we  place  most  reliance  on  our  quinine  dispenser.  In  each 
district  we  have  a  man  attached  to  the  dispensary  who  is 
known  as  the  quinine  dispenser.  He  spends  the  day  visiting 
the  various  squads  of  negroes  at  work.  He  offers  everybody 
in  the  squad  quinine.  He  gives  it  to  them  as  they  prefer,  either 
in  pill  or  solution.  We  do  not  attempt  to  use  compulsion  in 
the  matter.  Last  year  we  used  3,200  pounds  of  quinine.  Two- 
thirds  of  this  was  given  to  employees.  On  an  average  about 
half  of  our  force  gets  a  prophylactic  dose  of  quinine  each  day. 

Screening. — We  insist  upon  all  Government  buildings  being 
so  screened  as  to  keep  them  mosquito-proof  The  details  of 
screening  are  very  important.  It  should  always  be  under  the 
supervision  of  a  sanitarian  who  understands  these  details.  As 
the  sanitary  work  progresses,  screening  becomes  less  and  less 


350     MALARIA  PREVENTION  ON  ISTHMUS  OF  PANAMA  [Sect. 

necessary.  In  the  older  stations,  such  as  Ancon  or  Culebra, 
I  doubt  if  screening  is  now  necessary.  The  country  has  been 
so  thoroughly  drained  that  there  are  very  few  mosquitos,  though 
we  still  insist  upon  the  screening  just  as  carefully  as  we  did 
when  mosquitos  were  bad. 

Killing  mosquitos  in  quarters.  —  When  a  locality  has  been 
recently  occupied,  and  the  general  sanitary  work  has  not  had 
time  to  effect  malaria,  or  when  malaria  is  bad  from  other  causes, 
we  attempt  to  kill  the  infected  mosquitos.  As  daylight  comes 
on,  the  Anopheles,  when  she  has  had  her  fill  of  blood,  will  not 
in  general  leave  the  building  where  she  has  fed,  but  will  seek 
some  dark  corner  in  which  to  spend  the  day.  Taking  advantage 
of  this  we  have  a  man  go  around  and  kill  all  the  mosquitos  he 
can  find  in  the  building.  In  this  way  most  of  the  infected 
mosquitos  are  killed  before  they  become  infectious.  This 
method  is  particularly  efficacious  in  tents  and  small  buildings. 
It  is  surprising  what  results  can  be  obtained  by  this  method  in 
properly  selected  cases. 

Cost. — The  total  cost  of  sanitation  on  the  Isthmus  ^  for  the 
past  five  years  has  averaged  annually  about  three  dollars  and 
a  half  per  capita  for  the  whole  population  on  the  strip.  During 
that  time  this  population  has  averaged  100,000.  As  the  general 
result  of  this  expenditure  our  death-rate  for  the  total  population 
on  the  Zone  has  fallen  from  a  maximum  of  6772  per  thousand 
in  July  1906  to  2r52  in  December  1909.  The  rate  for  1905 
was  49-94  ;  1906—48-37  ;  1907—33-63  ;  1908—24-83  ;  1909— 
18-19.  The  death-rate  among  employees  for  disease  has 
fallen  from  a  maximum  of  62-15  i^i  July  1906  to  10-13  in 
December  1909. 

Of  the  yearly  expenditure  of  $3-50  per  capita,  I  estimate 
that  $2-oo  per  capita  is  spent  on  mosquito  work.  This 
expenditure  has  accomplished  the  total  eradication  of  yellow 
fever.  The  last  case  on  the  Isthmus  occurred  in  Colon  in  May 
1906.  It  has  reduced  the  deaths  from  malaria  in  the  total 
^  Wages  are  high  in  Panama. — R.  Ross. 


42]  RESULTS  351 

population  from  a  maximum  of  i6'2i  per  thousand  in  July 
1906  to  2"58  per  thousand  in  December  1909. 

Among  employees  it  has  reduced  the  deaths  from  malaria 
from  a  maximum  of  ii"59  per  thousand  in  November  1906,  to 
r23  per  thousand  in  December  1909.  The  admission  rate 
among  employees  has  fallen  from  a  maximum  of  1263  per 
thousand  in  July  1906  to  191  per  thousand  in  December  1909. 
The  admission  rate  per  thousand  for  malaria  among  employees 
has  been  as  follows:  1904,  125;  1905,  514;  1906,  821;  1907, 
424;  1908,  282;   1909,  215. 

Wherever,  in  this  article,  I  have  used  the  expression  so 
many  per  thousand  for  a  month,  I  mean  on  the  basis  of  a  year. 
If  I  say  the  death-rate  was  ten  per  thousand  for  July,  1909,  I 
mean  that  if  the  number  of  deaths  and  population  had  continued 
the  same  for  the  year  that  they  were  for  July  the  rate  would  be 
ten  per  thousand  per  year. 

I  think  that  the  mosquito  work  already  done  at  Ismailia, 
Havana,  Panama,  and  other  places  has  demonstrated  that 
malaria  can  be  controlled  and  eventually  banished  from  even 
the  worst  places  in  the  tropics,  and  this  at  no  very  great 
expense.  I  think  that  the  individual  farmer  can  go  anywhere 
into  tropical  countries  and  be  free  from  malaria  if  he  will  drain 
the  land  and  clear  brush  within  a  hundred  yards  about  his 
house.  And  in  addition  screen  his  house  so  carefully  that 
mosquitos  cannot  gain  access.  This  will  not  cost  him  anything 
like  as  much  as  he  expends  in  protecting  himself  against  the 
cold  of  Dakota  or  Manitoba. 

Notes  by  R.  Ross. — Dr  H.  R.  Carter,  the  distinguished  discoverer  of 
"extrinsic  incubation"  in  yellow  fever,  and  until  recently  Director  of 
Hospitals  in  the  Panama  Canal  Zone,  writes  me  a  letter  from  which  I  am 
permitted  to  quote  the  following : — "  Independently  of  the  general  results  as 
shown  in  the  general  statistics,  there  have  been  some  —  a  number  —  of 
beautiful  examples  of  the  results  of  anii-Anopheles  work  :  Caballo  Viego, 
falling  from  an  admission  rate  of  1675%  per  week  to  3%  within  two  months  ; 
Porto  Bella  from  10-12%  to  3%  and  finally  to  1-5%  ;  Juan  Grande  the  same  ; 
La  Boca  exceedingly  bad  in  1905,  and  in  1907  the  least  malarial  station  in 
the  Isthmus;  Carroval,  bad  in   1905  and  considered  almost  uninhabitable 


352  MALARIA  PREVENTION  ON  ISTHMUS  OF  PANAMA  [Sect.  42 

in  French  times,  one  of  the  most  healthful  places  from  1906  on.  It  was 
beautiful  work.  Not  all  'beer  and  skittles'  by  any  means,  but  beautiful 
work  all  the  same.  It  is  work,  however,  that  depends  absolutely  on  the 
perfection  of  its  details  ;  like  aseptic  surgery."  See  also  Dr  Carter's  article 
[1909]  for  a  brief  but  clear  analysis  of  the  subject. 

S.  T.  Darling,  M.D.,  has  kindly  informed  me  that  the  Panama 
Anophelines  which  carry  malaria  are  A.  {Cellia)  albimanus ;  A.  {Cellia) 
argyrotarsis  ;  A .  pseudopunctipennis ;  and  A.  tarsimaculata.  See  also  his 
papers  [1909,  19 10],  and  Section  65  (4). 


By  J.   A.   LE   PRINCE,  C.E.A.M. 

Chief  Sanitary  Inspector,  Panama  Canal  Zone 

43.  Anti  -  malarial  Work  on  the  Isthmus  of  Panama ; 
Technics. — As  we  approach  the  tropics,  where  the  rate  of. 
growth  of  vegetation  and  rainfall  increases,  the  cost  of  main- 
taining open  ditches  and  keeping  them  free  from  Anopheles 
larvae  increases  considerably.  In  the  north  the  greater  part 
of  the  rainfall  occurs  at  a  season  of  the  year  when  mosquito 
life  is  dormant.  Well-made  surface  ditches  will  need  very 
little  attention,  and  those  having  a  fair  grade  will  often  be 
dry  during  the  greater  part  of  the  Anopheles  breeding  season. 
Here  we  have  conditions  that  are  different,  and  which  are 
very  favourable  to  the  development  of  mosquito  life.  Our 
rainy  period  lasts  for  seven  or  eight  months.  The  ground 
remains  wet  for  many  days  at  a  time,  and  the  dense  vegeta- 
tion prevents  evaporation  of  surface  water  to  a  large  extent. 
Most  of  our  ditches  contain  water  continuously  throughout 
the  wet  season  and  well  into  the  dry  season.  It  is  not  un- 
usual to  have  rain  or  showers  occur  during  twenty-six  days 
out  of  thirty.  Such  conditions  keep  the  vegetation  in  open 
ditches  growing  rapidly,  and  are  favourable  to  the  develop- 
ment of  growths  of  algae.  The  latter  play  a  prominent  part 
in  the  development  of  Anopheles  larvae.  If  the  ditches  are 
not  kept  free  from  vegetation,  Anopheles  larvae  will  generally 
be  found,  and  the  number  thereof  seems  to  increase  when 
algae  are  present.  It  is  necessary  to  have  as  few  ditches  as 
we  can  possibly  get  along  with.  The  flatter  the  ditch  the 
more  the  likelihood  of  it  becoming  a  propagation  area.  Also, 
as   we   know  that  the   larvae  have  the  habit   of  collecting   in 

353  z 


354  ANTI-MALARIAL  WORK  ON  ISTHMUS  OF  PANAMA  [Sect. 

still  water,  or  in  water  having  a  low  velocity,  it  is  necessary 
to  keep  the  ditches  of  uniform  cross-section  and  free  from 
obstructions.  If  this  be  not  done  larvae  from  up-stream  will 
probably  find  safe  resting-places  at  points  lower  down.  At 
times,  when  all  other  insect  life  has  been  washed  down-stream, 
these  larvae  may  be  seen  clinging  to  the  bank  of  the  ditch. 

In  connection  with  open  ditches,  it  should  be  stated  that 
hard  showers  of  short  duration  are  a  temporary  help  in  that 
they  clean  out  the  ditches  and  remove  all  larvae.  Very  often, 
however,  hard  rains  will  practically  ruin  a  ditch  and  make 
regrading  necessary.  A  most  important  source  of  Anopheles 
on  the  Isthmus  is  the  seepage  water  ^  that  outcrops  on  hill- 
sides or  on  low  ground  near  the  foot  of  a  hill.  Such  productive 
areas  may  last  for  short  or  long  periods,  and  may  occur  at 
irregular  intervals.  If  the  quantity  of  seepage  water  be  small 
it  may  not  be  noted.  In  case  it  occurs  near  a  settlement, 
such  an  area,  even  though  small,  may  and  often  does  become 
the  cause  of  a  large  increase  in  the  previously  low  malarial 
sick-rate ;  and,  moreover,  extra  attention  will  probably  be  given 
to  anti-malarial  work  at  more  distant  points,  while  the  real 
source  of  the  trouble  may  have  escaped  attention. 

Sub-drainage  is  far  superior  to  open  ditches  in  every  way, 
and  should  be  used  whenever  conditions  are  favourable  therefor. 
It  is  much  more  economical  and  better  than  the  application 
of  larvicide  under  such  conditions  as  exist  here,  for  it  is 
always  possible,  even  with  the  most  careful  inspection,  for 
numerous  small  wet  areas  to  be  missed. 

The  practice  here  is  to  cut  off  seepage  water  by  means 
of  intercepting  ditches  containing  drain  tile.  In  all  cases 
locations  and  plans  of  such  ditches  should  be  made  at  the 
height  of  the  rainy  season,  when  the  worst  conditions  occur. 
If  this  is  not  done  errors  will  surely  be  made,  and  during 
extra  long  rainy  periods  seepage  water  will  occur  on  the  up- 
hill side  of  the  tile  line.  Ditches  for  sub-drainage  must  be 
^  /.^.,  Water  which  oozes  out. — R.  Ross. 


43]  TECHNICS    OF    DRAINAGE  355 

cut  to  true  grade,  and  should  be  made  as  narrow  as  possible 
so  as  to  reduce  the  amount  of  cover  stone  needed.  The  tile 
should  be  laid  to  true  grade  with  open  joints  of  about 
1/8  inch,  and  then  be  covered  with  stones  corresponding  to 
field  stone  of  about  4  to  6  inches  in  diameter.  The  dirt 
from  the  trench  must  be  placed  on  the  downhill  side  of  the 
tile  line  to  prevent  it  washing  back  into  the  ditch.  When 
the  soil  uphill  from  the  ditch  is  covered  with  vegetation  the 
space  between  the  cover  stones  does  not  fill  up.  Water  will 
find  its  way  into  the  tile  line  through  the  joints.  We  find 
that  the  flow  of  water  in  drain  tile  thus  laid  always  carries 
such  fine  silt  and  sand  as  enters  through  the  joints  of  adjacent 
sections,  provided  the  grade  is  about  1%  for  6-inch  tile  and 
not  less  than  one  half  of  1%  for  lo-inch  tile,  when  there  is 
no  loose  soil  above  the  line  of  the  ditch.  Special  care  should 
be  taken  to  have  the  outlet  of  the  tile  kept  clear  at  all  times. 
When  tile  drains  are  located  and  laid  properly  they  are  the 
most  economical  method  of  draining  for  anti-malarial  work, 
and  the  cost  of  maintenance  is  very  small.  Some  drains  laid 
three  and  a  half  years  ago  have  not  cost  one  cent  for 
maintenance  since  installation.  Due  to  washouts,  erosion, 
necessity  of  frequent  regrading,  cleaning,  removal  of  vegetable 
growth,  algae,  etc.,  the  cost  of  maintaining  open  ditches  is 
often  expensive  and  necessarily  continuous.  If  such  mainte- 
nance costs  are  or  will  be  excessive,  and  conditions  such  as 
grade,  character  of  soil,  etc.,  are  unfavourable  for  sub-drainage, 
we  make  the  ditches  the  shape  of  a  flat  "  V,"  and  line  them 
with  flat  stone  laid  in  just  sufficient  cement  mortar  to  hold 
them  together,  leaving  sufficient  weep  holes  near  the  rounded 
floor  to  take  care  of  ground  water.  Frequently  here  the  cost 
of  maintaining  an  open  ditch  for  two  or  three  years  will  be 
more  than  that  of  lining  the  ditches  permanently  with  flat 
stone.  Near  some  of  the  camps  such  lining  of  ditches  costs 
from  25  to  50  cents  per  running  foot,  and  as  the  same  ditches 
cost  previously  about  25  cents  per  foot  per  year  to  maintain. 


356  ANTI-MALARIAL  WORK  ON  ISTHMUS  OF  PANAMA  [Sect. 

the  advantage  of  the  permanent  work  is  self-evident.  Stone- 
lined  ditches  are  very  seldom  sources  of  Anopheles.  Filling 
is  sometimes  necessary  in  low  lands  that  cannot  be  drained, 
and  under  certain  circumstances  it  should  be  accomplished, 
providing  the  cost  is  not  prohibitive. 

A  large  number  of  Anopheles  larvae  may  occur  on  flat 
lands  where  water  collects  in  small  quantities  in  numerous 
places.  Although  much  of  the  water  may  evaporate,  and  the 
breeding  -  places  dry  up  before  the  larvae  can  develop  into 
adults,  yet  what  usually  happens  is  that  a  sufficient  number 
of  the  small  wet  places  remain,  which,  taken  together,  will 
produce  during  the  rainy  season  sufficient  adult  mosquitos  to 
keep  a  near-by  settlement  well  supplied.  All  very  small  as 
well  as  large  wet  places  that  are  not  thoroughly  dry  during 
a  period  of  ten  days  need  attention. 

Evaporation  of  the  surface-water  can  be  largely  increased 
by  the  removal  of  the  vegetation.  In  fact,  in  many  such  areas 
we  find  that  the  larvae  develop  only  when  the  grass  and 
vegetation  are  sufficiently  high  to  retard  evaporation.  Where 
the  water  continues  to  remain  after  the  removal  of  all  vegeta- 
tion it  will  often  be  necessary  to  apply  larvicide.  In  case  the 
breeding  areas  cover  a  large  territory,  the  transportation  and 
proper  application  of  the  larvicide  may  cost  several  times  more 
than  the  larvicide  itself  Then  it  becomes  necessary  to  use 
some  form  of  concentrated  larvicide  in  order  that  the  labourers 
may  employ  nearly  all  of  their  time  in  applying  it  rather  than 
in  its  transportation.  After  much  unsuccessful  experimenta- 
tion with  commercial  larvicides  it  was  found  that  a  mixture 
of  carbolic  acid,  resin  and  caustic  soda  has  very  satisfactory 
larvicidal  properties  and  acts  promptly.  It  meets  the  con- 
ditions that  we  have  to  contend  with  fairly  well.  It  costs  less 
than  one-half  of  the  best  commercial  larvicide  w^e  could  obtain, 
and  the  latter  was  apparently  not  standardised.  One  part  of 
this  mixture  placed  in  five  thousand  parts  of  water  containing 
mosquito  larvae  will  kill  them  all   in  less  than    five    minutes. 


43]  LARVICIDE  357 

When  one  part  is  applied  to  eight  thousand  parts  of  water 
containing  larvae,  the  same  will  be  killed  in  thirty  minutes. 

The  method  of  preparing  it  is  as  follows : — Crude  carbolic 
acid,  containing  about  1 5%  of  phenol,  is  heated  to  212  degrees  F., 
finely  pulverised  resin  is  added,  and  the  mixture  kept  boiling 
until  the  resin  is  all  dissolved.  Caustic  soda  is  then  added, 
and  the  solution  kept  at  212  degrees  F.  for  about  ten  minutes, 
or  until  a  perfectly  dark  emulsion  without  sediment  is  obtained. 
The  mixture  is  thoroughly  stirred  from  the  time  the  resin  is 
added  until  the  end.  As  the  composition  of  crude  carbolic 
acid  varies  greatly,  the  proportion  of  ingredients  of  the  larvicide 
will  vary,  and  it  is  necessary  to  have  small  experimental  lots 
made  in  the  laboratory,  and  tested  before  the  batch  of  larvicide 
for  use  in  the  field  is  manufactured.  The  average  mixture  is 
about  as  follows : — 300  gallons  crude  carbolic  acid  ;  200  lbs. 
resin ;  30  lbs.  caustic  soda.  The  larvicide  costs  us  about 
14  cents  a  gallon. 

In  lagoons,  ponds  and  lakes  near  settlements  we  get  rid 
of  the  vegetation  so  far  as  possible,  and  at  the  edges  where 
the  water  is  shallow,  and  in  other  places  where  larvae  occur, 
we  destroy  them  with  this  larvicide. 

When  numerous  small  particles  of  dead  vegetable  matter 
that  are  washed  into  lakes  or  ponds  are  collected  by  the  wind, 
the  Anopheles  lays  her  eggs  in  amongst  this  debris^  and  it  must 
be  removed. 

In  long  running  streams  and  open  ditches  where  anti- 
malarial work  is  being  done  crude  petroleum  may  be  used, 
and  it  is  more  effective  when  applied  automatically.  Should 
the  quantity  of  running  water  be  small,  so  that  not  much  oil 
is  needed,  then  a  handful  of  cotton  waste  tied  in  a  bundle  is 
soaked  in  oil  for  a  day,  and  then  placed  near  where  the  water 
outcrops.  The  water  passing  by  this  waste  becomes  covered 
with  a  very  thin  film  of  oil.  The  waste  gives  off  an  oil  film 
for  about  ten  or  fourteen  days,  and  is  then  resoaked  in 
oil  and  used  aerain.     For  larger  bodies  of  water  having  a  fair 


358  ANTI-MALARIAL  WORK  ON  ISTHMUS  OF  PANAMA  [Sect. 

velocity,  drip  cans  or  drip  barrels  are  used,  and  should  be 
located  2  feet  above  the  water  surface  to  break  up  the  oil  drops 
as  they  fall.  They  are  made  as  follows : — A  piece  of  metal 
similar  to  that  of  a  flat  wick  lamp  that  holds  the  flat  wick  is 
fastened  to  the  barrel  or  can  near  its  base.  This  wick  chamber 
is  made  somewhat  larger  than  the  wick,  so  that  the  wick  may 
fit  it  loosely  when  saturated  with  fuel  oil.  The  space  inside 
the  barrel,  between  the  wick  chamber  and  the  bottom  of  the 
barrel,  is  filled  with  a  solution  of  caustic  soda  or  larvicide.  As 
the  oil  passes  along  the  wick  it  comes  into  contact  with  the 
caustic  soda,  and  is  "  cut "  or  rendered  thinner.  This  prevents 
the  wick  from  becoming  clogged  by  the  thick  fuel  oil.  The  wicks 
seldom  clog,  but  in  case  such  occurs  some  larvicide  is  dropped 
on  the  wick.  This  cleans  it,  and  makes  it  as  serviceable  as 
before. 

Adult  Anopheles  may  persist  near  settlements  when  it  is 
supposed  that  all  that  is  possible  has  been  done  toward  their 
eradication.  Near  the  seashore  the  larvae  of  some  species  of 
Anopheles  occur  in  water  that  is  quite  brackish.  All  brackish 
water  should  be  considered  as  capable  of  supporting  Anopheles 
larvae  until  the  contrary  is  proved  to  be  true.  Also  mud  from 
above  which  the  water  has  recently  disappeared  should  be 
looked  on  with  suspicion,  and  treated  when  it  supports  mosquitos. 
Many  small  muddy  areas  may  contain  no  mosquito  life,  but 
if  the  larvae  are  present  in  some  small  spots,  the  sum  total  of 
such  possible  places,  most  of  which  are  hidden  by  the  grass 
and  not  easily  seen,  is  worthy  of  consideration.  The  adults 
that  may  develop  therefrom  in  rainy  periods  are  often  numerous. 
Larvae  may  only  be  present  in  one  or  more  particular  parts 
of  a  large  possible  breeding-area,  and  a  superficial  inspection 
thereof  will  be  misleading.  Dipping  with  a  cup  is  a  very 
unsatisfactory  way  to  determine  the  presence  of  larvae.  Even 
when  larvae  cannot  be  dipped  up  from  a  small  shallow  body 
of  water,  if  the  same  is  stirred  up  the  larvae  will  often  appear 
promptly  at  the  surface.     When  no  larvae  can  be  seen  it  does 


43]  DESTRUCTION    OF   LARVAE  359 

not  always  mean  that  none  are  present.  We  use  the  larvicide 
appHcation  method  to  determine  the  presence  or  absence  of 
larvae  to  a  large  extent.  When  applying  strong  solutions  of 
larvicide  at  the  edges  of  a  large  body  of  water  it  is  noticed 
that  the  larvae  appears  to  lose  all  sense  of  direction.  Very 
few  reach  the  clear  water,  and  nearly  all  that  do  so  die  soon 
afterwards.  Our  labourers  are  supplied  with  knapsack  sprayers 
for  distributing  larvicide,  and  a  labourer  can  take  enough 
larvicide  along  with  him  to  last  for  several  hours  of  spreading. 
The  cost  of  spreading  a  dollar's  worth  of  crude  oil  by  hand 
often  amounts  to  two  dollars  or  more. 

So  far  as  we  can  determine  not  much  malaria  is  actually 
contracted  by  labourers  while  outside  on  the  work.  In  fact 
we  have  no  case  on  record  where  a  person  has  been  bitten  on 
the  Isthmus  by  an  Anopheles  when  the  person  was  exposed  to 
the  direct  rays  of  the  sun.  Although  we  think  very  little 
infection  is  conveyed  during  working  hours  out  in  the  sunlight, 
we  do  know  that  it  is  a  common  occurrence  for  persons  to  be 
bitten  in  the  daytime  by  Anopheles  when  both  are  inside  of 
buildings.  We  have  noted  that  a  person  indoors  may  be  bitten 
several  times  in  a  period  as  short  as  ten  minutes,  and  that 
Anopheles  while  indoors  will  take  blood  at  any  time  between 
daylight  and  dark,  as  well  as  at  night. 

In  connection  with  the  prevention  of  malaria,  the  destruction 
of  adult  Anopheles  in  barracks,  tents  and  other  crowded  quarters 
is  certainly  worthy  of  attention. 

The  screening  of  buildings  is  of  importance.  To  keep  the 
screening  intact  and  effective  is  quite  a  problem  where  ignorant 
labourers  are  concerned.  A  screened  building  is  far  superior  as 
a  preventative  measure  to  the  use  of  mosquito  bars  over  each 
cot.  The  latter,  as  used  by  labourers,  is  generally  of  little  value. 
The  American  housewife  on  the  Isthmus  is  interested  in  keeping 
the  screened  doors  closed  in  order  to  keep  out  mosquitos  and 
flies.  The  children  and  wives  of  American  employees  have  been 
particularly  free  from  malaria,  and  in  fact  do  not  contract  malaria 


36o  ANTI-MALARIAL  WORK  ON  ISTHMUS  OF  PANAMA  [Sect. 

on  the  Isthmus  as  often  as  they  would  in  many  parts  of  the 
United  States. 

During  February  of  1907  a  census  of  American  women  and 
children  then  in  the  territory  between  Bohio  and  Balboa  was 
taken.  There  were  552  women  and  345  children  present.  Some 
of  them  had  come  to  the  Isthmus  in  1904  and  1905,  but  the 
greater  part  in  1906.  The  malarial  sick-rate  in  1905,  1906  and 
1907  was  very  much  higher  than  it  is  to-day.  Among  the  897 
women  and  children,  82%  had  not  had  malarial  fever  between 
the  time  they  arrived  here  and  up  to  the  time  the  census  was 
taken.  During  the  same  period  some  of  the  labourers'  camps 
had  a  10%  malarial  hospital  sick-rate  per  week.  Of  the  American 
children  on  the  Isthmus  in  February  1907,  90%  had  not  yet  had 
malaria.  At  Bohio,  where  the  houses  were  not  screened,  there 
were  seven  American  children  and  seven  American  women  in 
February  1907.  Three  of  the  women  and  three  of  the  children 
had  had  malarial  attacks  since  arrival  at  Bohio. 

A  temporary  camp  consisting  of  tents  was  established  at 
Cocoli  during  April  1908.  Anopheles  breeding-places  occurred 
on  all  sides,  and  we  could  not  possibly  get  rid  of  them  without 
considerable  expenditure  of  funds.  The  size  of  the  camp  did 
not  warrant  much  expenditure.  Adult  Anopheles  were  very 
numerous  about  the  camp,  and  thirty  or  more  could  be  counted 
in  a  single  tent  in  the  daytime.  A  watchman  was  employed 
to  kill  off  all  mosquitos  seen  in  the  tents  during  the  daytime. 
This  watchman  kept  on  the  go  from  tent  to  tent.  All  mosquitos 
in  the  tent  were  within  reach,  which  was  a  very  important  advan- 
tage. No  work  was  done  by  the  watchman  after  5  p.m.  At 
first  Anopheles  were  so  numerous  that  a  tent  could  not  be  left 
for  a  half-hour  without  some  coming  in.  The  near-by  breeding- 
places  were  oiled  in  order  to  reduce  the  number  of  adults,  but 
many  remained.  The  destruction  of  adults  began  loth  April 
1908,  and  between  that  time  and  24th  August  1908  there  were 
seventeen  cases  of  malaria  at  Cocoli,  which  would  mean  only  a 
little  over  i^  of  the  force  were  sick  with  malaria  during  each 


43]  DESTRUCTION   OF   ADULTS  361 

period  of  seven  days.  The  camp  was  abandoned  on  24th 
August  1908. 

This  was  a  lower  sick-rate  than  had  occurred  at  other  camps 
where  anti-malarial  work  had  been  carried  out  for  quite  some 
time,  but  at  Cocoli  we  were  killing  adult  mosquitos,  and  the 
other  places  were  not. 

As  this  work  resulted  so  successfully  it  has  since  been  carried 
out  at  labourers'  barracks  at  various  stations,  and  has  undoubtedly 
been  an  important  item  in  the  marked  decrease  of  the  malarial 
rate  that  has  occurred  during  the  past  year. 

Recently  some  six  hundred  Anopheles  (mostly  albipes)  were 
collected  alive  in  various  camps  where  the  adult  Anopheles  are 
being  systematically  destroyed  daily  in  barracks.  They  were 
examined  by  Dr  S.  T.  Darling,  Chief  of  the  Board  of  Health 
Laboratory,  and  not  a  single  one  showed  malarial  parasites. 
It  seems  fairly  evident  that  we  catch  most  of  the  Anopheles 
between  the  time  they  first  enter  the  barracks  and  the  time 
when  they  should  become  infective.  The  catching  of  adults  in 
the  buildings  which  have  high  walls  or  in  dark  rooms  is  a  much 
more  difficult  proposition  than  their  destruction  in  low  tents, 
where  all  can  easily  be  seen  and  reached.  It  would  be  a  large 
advantage  to  have  the  interior  of  buildings  painted  a  light  colour 
or  white- washed  so  that  Anopheles  could  be  readily  seen  when 
resting  on  the  walls.  We  now  use  test-tubes  containing  cotton 
wool  and  chloroform  to  destroy  adults  resting  on  walls,  etc.  It 
is  quieter  than  the  slapping  method,  and  very  few  mosquitos 
are  frightened  away. 

At  the  base  of  Diablo  Hill  is  a  swampy  area  about  two  miles 
long  and  a  half  a  mile  wide.  It  cannot  be  drained  at  the  present 
time.  From  the  top  of  the  hill  to  the  water-line  is  about  200 
yards.  In  June  of  1908  several  hundred  United  States  Marines 
were  stationed  at  Camp  Diablo,  and  remained  on  this  hill  for 
about  six  or  eight  weeks.  The  conditions  affecting  malaria, 
such  as  drainage,  etc.,  were  then  the  same  as  they  are  to-day. 
While  the  Marines  were  in  the  camp  their  malarial  sick-rate 


362  ANTI-MALARIAL  WORK  ON  ISTHMUS  OF  PANAMA  [Sect. 

was  2^  per  day,  or  14%  per  week.  Since  that  time  a  string  of 
railroad  cars  in  which  the  labourers  of  the  railroad  construction 
gang  sleep  was  located  near  the  foot  of  the  hill,  and  between 
the  swarap  and  the  camp  formerly  occupied  by  the  Marines. 
During  the  past  thirty  weeks  an  average  of  forty-four  Anopheles 
per  day  have  been  destroyed  each  morning  in  these  cars.  They 
were  caught  in  chloroform  tubes  as  above  described.  It  takes 
the  labourer  thirty  minutes  each  morning  to  do  this  work.  The 
cost  is  5  cents  per  day,  or  30  cents  per  week,  and  the  destruc- 
tion is  carefully  performed  by  a  competent  man.  From  the 
first  week  in  May  1909  to  30th  November  1909,  which  is  the 
rainy  season,  only  four  cases  of  malaria  have  occurred  among 
the  forty  labourers  sleeping  in  these  cars,  or  about  one  man  in 
300  men  working  for  a  period  of  seven  days,  although  they  were 
more  freely  exposed  to  the  Anopheles  than  the  Marines  had  been. 
This  work  of  destruction  of  adults  in  quarters  costs  so  little 
that  undoubtedly  it  will  be  of  value  in  all  malarial  districts 
where  house  tenants  are  interested  in  the  prevention  of  malaria. 
It  will  be  of  special  importance  where  an  army  is  in  camp,  or 
where  railroad  camps  are  established  in  malarial  districts,  as 
with  proper  care  the  sick-rate  could  by  this  means  be  kept  far 
below  what  it  would  otherwise  be.  On  the  Isthmus  we  consider 
such  work  as  supplementary  to  the  drainage  and  other  anti- 
malarial measures. 

It  should  be  noted  that  most  of  the  labourers'  camps  in  the 
Canal  Zone  are  located  near  native  towns,  and  undoubtedly 
a  large  percentage  of  what  malaria  we  do  have  is  contracted 
by  our  labourers  spending  their  evenings  at,  or  living  at  the 
native  settlements.  Nevertheless,  in  spite  of  continuous  topo- 
graphical changes,  constant  rains,  native  villages  and  numerous 
other  difficulties,  the  malarial  sick-rate  is  being  steadily  and 
systematically  decreased  year  after  year.  The  decrease  of  adult 
Anopheles  to  be  found  at  the  camps  is  equally  noticeable. 

Several  years  ago  it  appeared  that  the  malarial  sick-rate 
would  always  be  much  higher  during  the  rainy  season  than  in 


43]  RESULTS   AT   HAVANA  363 

the  dry  season,  but  during  the  past  two  years  the  Department 
of  Sanitation  have  been  able  to  control  the  situation  to  such  an 
extent  that  at  some  of  the  larger  settlements  there  has  been  no 
appreciable  increase  in  the  number  of  malarial  cases  during  the 
wet  season  as  compared  with  the  dry  season.  It  is  of  interest 
to  note  that  this  has  occurred  in  those  districts  where  during 
previous  years  the  increase  of  malaria  closely  followed  the 
increase  of  rainfall.  This  is  very  encouraging,  considering  that 
such  results  have  been  obtained  where  the  settlements  are 
scattered  over  large  areas. 

With  regard  to  the  destruction  of  adult  Anopheles  in  dwell- 
ings it  should  be  stated  that  malaria  cannot  always  be  controlled 
by  this  means  only,  although  it  was  fairly  successful  at  Diablo 
and  Cocoli.  The  colour  of  the  house  walls,  height  of  the  ceiling, 
the  amount  of  light  in  rooms  and  the  number  of  hiding-places, 
etc.,  effect  the  percentage  of  adults  that  may  be  destroyed. 
Again,  if  persons  living  in  houses  that  are  inspected  daily  visit 
houses  that  are  not  so  treated,  or  are  infected  elsewhere,  the 
results  will  not  be  as  satisfactory  as  where  their  camp  is  iso- 
lated as  was  the  case  at  Cocoli  and  at  Diablo.  Drainage  and 
eradication  of  breeding-areas  is  the  all-important  work  in  an 
anti  -  malarial  campaign.  The  catching  of  adults  should  be 
considered  as  supplementary  to  drainage,  screening,  application 
of  larvicide,  etc.  At  Havana  we  relied  exclusively  on  drainage 
and  filling.  Most  of  the  natives  there  do  not  like  to  take 
quinine.     Malaria  at  Havana  has  practically  been  eradicated. 

Data  relating  to  charts  showing  reduction  of  malaria  in  the 
Canal  Zone. — Chart  No.  i  shows  the  percentage  of  all  Canal 
employees  (malarial  cases  only)  that  were  sent  to  the  hospital 
each  month  from  1906  to  1909  inclusive.  Attention  is  invited 
to  the  fact  that  the  sick-rate  is  always  lowest  about  May  or 
at  the  end  of  the  dry  season.  That  the  malarial  sick  -  rate 
would  advance  rapidly  in  former  years  with  the  arrival  of  the 
wet  season  June,  July  and  August.  This  advance  has  been 
materially  checked.  Compare  the  wet  season  record  of  1909 
(June  to  December)  with  the  same  period  of  the  previous  years 


364  ANTI-MALARIAL  WORK  ON  ISTHMUS  OF  PANAMA   [Sect. 

and  with  the  dry  season  of  1909  (January  to  May).  The 
successive  yearly  reductions  are  a  fair  index  of  the  value  of  the 
anti-malarial  work. 

The  successive  months  are  plotted  one  half  inch  apart, 
horizontal  measurement.^  The  percentage  malarial  sick-rate  is 
plotted  on  the  vertical  lines,  on  a  scale  of  two  inches  vertical 
measurement,  equals  i^.  If  the  force  employed  consisted  of 
40,000  men,  and  500  of  them  are  sent  to  the  hospital  with 
malaria  during  a  month,  then  the  rate  on  Chart  No.  i  for  that 
month  would  be  plotted  as  r25^. 

Chart  No.  2  is  a  record  of  malarial  cases  among  employees 
at  Porto  Bello.  The  percentage  sick-rate  for  each  week  plotted. 
This  was  a  new  camp  that  was  opened  up  a  few  weeks  before 
anti-malarial  work  started.  At  all  newly  opened  camps  the 
malarial  rate  runs  high,  as  compared  with  areas  where  anti- 
malarial work  is  being  done.  Without  doubt  the  rate  would 
remain  high  if  no  anti-malarial  work  were  done.  Note  that 
preventive  work  at  Porto  Bello  started  21st  March  1908,  and 
that  the  rate  from  then  to  June  averaged,  say,  about  3^  per 
week.  Or,  over  12^  of  employees  were  sent  to  hospital  per 
month  (malarial  cases),  and  many  of  the  labourers  remaining 
at  work  were  not  in  physical  condition  to  do  as  much  work  as 
they  are  capable  of  doing  to-day.  That  during  this  same 
period,  among  employees  in  the  Canal  Zone,  the  monthly  sick- 
rate  (malaria  only)  was  not  much  over  i^.  (See  Chart  No.  i.) 
About  600  men  are  located  at  Porto  Bello, 

Chart  No.  3  is  a  record  of  malaria  at  Gorgona.  Present 
population  2,000  employees.  Compare  years  1908  and  1909 
with  the  previous  years.  No  large  increase  of  malaria  occurs  in 
the  wet  season  (June  to  December)  during  the  last  two  years. 
Anopheles  are  now  seldom  found  in  barracks,  which  indicates 
that  they  are  not  numerous.  Note  the  effect  of  the  wet  season 
on  the  malaria  rate  for  1906,  and  absence  of  same  for  wet 
seasons  of  1908  and   1909. 

In  Charts  No.  2  and  No.  3  the  weekly  sick-rates  are  given. 
^  The  accompanying  charts  are  reduced. — R.  Ross. 


43]  RESULTS   AT   PANAMA  365 

For  instance,  during  the  week  ending  6th  January  1906  a 
number  of  the  employees  at  Gorgona  (Chart  No.  3)  were  sent 
to  the  hospital  whose  cases  were  diagnosed  as  malaria.  This 
number  consisted  of  274^  of  the  entire  working  force  living 
at  Gorgona  during  that  week.  The  dates  of  the  ending  of 
each  week  for  which  the  percentage  sick-rate  is  plotted  are 
given.  These  percentages  show  only  the  malarial  sick-rates 
and  not  the  other  hospital  cases. 

In  connection  with  Chart  No.  i  it  should  be  stated  that  in 
the  early  days  it  was  difficult  to  get  the  malarial  patients  from 
among  the  ignorant  labourers  to  go  to  the  hospital,  and  so  the 
actual  sick-rate  at  that  time  was  higher  than  what  has  been 
recorded.  At  the  present  time  the  labourers  go  voluntarily  to 
the  hospital  when  they  feel  sick.  Note  that  during  seven 
months  of  1906  the  rate  was  above  6%;  that  during  1907,  for 
ten  months,  the  rate  was  below  5%.  In  1908,  during  eleven 
months,  the  rate  was  below  4%.  In  1909,  the  rate  was  below 
3%.  The  highest  monthly  rate  during  the  wet  season  of  1909 
was  a  little  over  2//,  as  compared  with  4%,  5%  and  10% 
respectively  for  the  wet  season  of  the  years  1908,  1907  and  1906. 

Refer  again  to  Chart  No.  2,  relating  to  malaria  at  Porto 
Bello.  During  December  of  1909  the  number  of  rainy  days 
was  twenty-seven  out  of  thirty-one.  The  rainfall  was  45*03 
inches  for  November  and  58'i7  inches  for  December  1909,  as 
against  4173  and  2572  inches  respectively  for  November  and 
December  of  1908.  Such  conditions  of  rainfall  mean  a  large 
increase  in  the  number  of  possible  Anopheles  areas.  As  shown 
on  the  chart,  no  increase  of  malaria  occurred  due  to  the 
increased  wet  area  accessible  to  Anopheles. 

This  is  a  good  illustration  of  the  results  of  anti-malarial 
work  performed  under  severe  conditions  when  the  work  might 
at  first  sight  appear  to  be  almost  impossible  to  accomplish. 
From  1st  November  1908  to  2nd  January  1909,  5%  of  the  force 
were  sent  to  hospital  with  malaria.  From  31st  October  1909 
to  1st  January  19 10,  during  the  period  of  heavier  rainfall,  only 
3'26%  of  the  force  were  hospital  malaria  cases. 


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By  Sir  RUBERT  BOYCE,  F.R.S. 

Professor  of  Pathology,  University  of  Liverpool 

44.  Malaria  in  the  West  Indies.  —  There  is  no  doubt  that 
malaria  has  markedly  decreased  throughout  the  West  Indies. 
This  statement  can  be  verified  by  comparing  the  current  health 
reports  with  those  furnished  by  the  Surgeon-Generals  when 
the  various  islands  were  garrisoned.  The  factors  which  have 
brought  about  this  diminution  are  the  same  as  those  which 
have,  in  more  recent  time,  operated  in  towns  like  Bombay, 
New  Orleans,  Rio,  etc.,  and  which  at  a  still  earlier  period 
led  to  the  disappearance  of  malaria  from  a  large  portion  of 
Europe. 

It  may  now  be  stated  that  malaria  as  an  endemic  disease 
is  limited  to  the  country  districts  throughout  the  islands,  and 
that  it  ceases  at  the  outskirts  of  the  principal  towns,  in  a  few 
instances  penetrating  into  a  centre  of  population  along  the 
banks  of  some  neglected  marsh  or  stream. 

In  the  principal  towns  the  swampy  ground  which  almost 
invariably  surrounded  the  early  settlements  has  now  all  been 
reclaimed,  and  in  its  place  well-planned  streets  have  appeared. 
Properly-graded  roads  and  concrete  drains  are  the  rule  rather 
than  the  exception.  Since  the  year  1850  a  considerable  pro- 
portion of  the  larger  towns  received  the  immense  advantages 
of  a  pipe-borne  water-supply,  derived  from  reservoirs  or  rivers 
outside  the  towns.  This  system  at  once  did  away  with  the 
old-time  wells,  and  abolished,  or  greatly  decreased,  rain-water 
barrels   and    storage   tanks.     These    improvements,   coincident 

369  2  A 


370  MALARIA   IN   THE   WEST   INDIES  [Sect. 

with  the  progress  of  prosperity  and  the  appreciation  of  the 
laws  of  hygiene,  have  together  brought  about  the  cessation 
of  malaria  and  yellow  fever  as  endemic  diseases  in  the  chief 
towns.  Therefore  it  is  to  the  country  districts,  and  on  the 
plantations,  that  the  student  must  look  for  the  survival  of 
malaria  in  its  endemic  form.  And  there  is  no  doubt  that  it 
does  still  so  survive  throughout  the  Antilles,  as  an  analysis 
of  the  Registrar-General's  or  the  Medical  Officer's  Mortality 
Returns  abundantly  proves.  Unfortunately,  it  is  very  difficult 
to  estimate  accurately  the  total  sickness  and  mortality  rates 
from  malaria  in  the  various  islands  ;  in  many  instances  the  causes 
of  death  in  50^  or  more  of  the  cases  is  not  definitely  stated. 
And,  of  course,  as  is  well  known,  although  the  anaemia  of 
malaria  may  have  had  the  chief  share  in  producing  lowered 
vitality,  yet  the  actual  cause  of  death  is  registered  as  perhaps 
bronchitis  or  consumption,  as  the  symptoms  of  these  affections 
were  the  more  obvious  ones  from  which  the  patients  suffered 
during  illness. 

Efforts  are  now  being  made,  however,  to  make  more  accurate 
estimates  of  malaria  by  the  employment  of  more  perfect  methods 
of  diagnosis,  such  as  spleen  rates  and  blood  examinations. 

Grenada. — Population,  68,253.  Capital,  St  George's  ;  popula- 
tion, 5,198. 

Malaria  is  still  prevalent  in  the  country  districts,  and  is 
endemic  and  imported.  In  No.  i  District  in  St  George's  Parish 
681  cases  and  22  deaths  were  recorded  in  1906,  and  317  cases 
and  12  deaths  in  1907.  In  No.  6  District  1,119  cases  were 
reported  in  the  same  year.  The  malaria  is  due  to  the  breeding 
of  Anophelines  in  certain  swampy  lands  and  puddles,  and,  in 
the  wet  season,  perhaps  also  to  the  presence  of  water-holding 
epiphytes  upon  the  shade  trees  on  the  cocoa  plantations. 

Preventive  Measures : — 
I.  Introduction  of  pipe-borne  water.     This  was  the  first  step 
which  led  to  the  reduction  of  Anophelines  in  the 


44]  GRENADA,   ST   VINCENT  371 

towns  of  St  George's,  Gouyave  and  Grenville  by  doing 
away  with  numerous  barrels  and  odd  water  containers. 

2.  Road-making  and  street  drainage  in  the  towns. 

3.  Government  and  medical  officers  throughout  the  colony 

making  returns  of  all  anti-malarial  measures  under- 
taken in  their  respective  districts. 

4.  1st  April  1909. — The  fish  "  millions  "  were  introduced  into 

the  colony  with  the  object  of  stocking  ponds  and 
large  collections  of  water. 

5.  The  Public    Health  Ordinance  of   1907  prohibited  the 

keeping  of  stagnant  water  unless  protected,  oiled 
or  stocked  with  fish,  and  all  odd  receptacles  were 
to  be  removed. 

6.  In  1902  and  1905  further  ordinances  were  promulgated, 

declaring  mosquito  breeding  -  places  in  and  about 
human  habitations  to  be  a  statutory  nuisance. 

7.  The  more  careful  cultivation  on  the  cocoa  estates  has 

led  to  better  drainage,  and  a  diminution  of  malaria 
on  the  estates. 

8.  Considerable  attention  is  now  paid  to  entomology. 

St  Vincent.  —  Population,  47,548.  Capital,  Kingstown  ; 
population,  4,547. 

Malaria  for  the  most  part  confined  to  small,  swampy  districts 
in  the  country.  The  Medical  Officer's  returns  show  525  cases 
in  1907,  and  281  cases  in  1908. 

Prophylaxis : — 

1.  Pipe-borne  water  has  led  to  great  diminution  of  water 

barrels  and  odd  receptacles  and  wells. 

2.  Construction  of  side  drains  and  roads. 

3.  Removal    of   odd   receptacles    from    yards,   and    better 

sanitary  supervision. 

4.  A  nti-larval  meastires — 

1901. — Measures  promulgated  against  stagnant  water,  unless 
oiled,  screened  or  stocked  with  fish. 


372  MALARIA   IN   THE   WEST   INDIES  [Sect. 

igoQ. — New   Public    Health   Ordinance,  with    provision 
against  stagnant  water  and  mosquito  larvae. 
5.  The  late  Dr  Branch  was  a  keen  entomologist,  and  did 
much  to  get  rid  of  breeding-grounds  of  mosquitos. 

Sf  Lucia. — Population,  50,000.     Capital,  Castries. 
There  is  still  a  small  amount  of  malaria,  due  to  a  few  low- 
lying,  swampy  patches  which  persist  near  Castries. 
Prophylaxis  : — 

1.  Introduction  of  pipe-borne  water  brought  about  a  great 

reduction  in  the  number  of  breeding-places. 

2.  Better  roads  and  side  drainage  undertaken  from   1890- 

1900. 

3.  Energetic   anti-mosquito    drainage    and    bush    clearing 

operations  undertaken  by  Major  Hodder. 

4.  Anti-mosquito   laws.  —  In    1906  the  Colonial    Secretary 

commenced  a  vigorous  systematic  campaign  against 

mosquitos,  by  causing  careful  returns  to  be  made  of 

all  insect -carried  diseases  and  of  the  breeding-places 

of  mosquitos. 
In  1907  regulations  were  framed  dealing  with  stagnant 

and  waste  water. 
In  1909  a  vigorous  house-to-house  campaign  amongst 

mosquitos  was  started. 
Fines  have  been  regularly  enforced   from   1907  against 

all  who,  after  caution,  refuse  to  get  rid  of  mosquito 

larvae. 

Trinidad. — Population,  336,769.  Chief  Town,  Port  of  Spain  ; 
population,  70,000. 

General  death-rate  for  1908,  10  per  milk. 

Total  deaths  from  malaria,  71  in  1908.  Total  amount  of 
malaria  small. 

Upon  the  estates,  however,  malaria  is  responsible  for  more 
than  half  of  the  gross  sickness  rate  amongst  the  indentured 
labourers. 


44]  TRINIDAD,    BRITISH    GUIANA  373 

Prophylaxis : — 

1.  Pipe-borne  water-supply. — This   system    was  first   intro- 

duced into  the  Port  of  Spain  as  far  back  as  185 1, 
and  has  since  then  been  largely  extended  throughout 
the  Port  of  Spain.  To  it  must  be  ascribed  the 
abolition  of  endemic  yellow  and  malarial  fevers, 
for  it  at  once  did  away  with  the  necessity  of  the 
numerous  water  barrels,  cisterns,  wells  and  odd 
receptacles  of  all  descriptions,  which  in  the  old 
days  were  the  breeding-places  of  the  mosquitos. 

2.  The  construction   of  well  -  graded    roads  and   concrete 

drains  everywhere  within  the  vicinity  of  the  town. 

3.  Concreting  backyards,  removal  of  rubbish  and  bush. 

4.  Education.  —  Systematic     training     of     the     sanitary 

inspectors,  schoolmasters  and  others  throughout 
the   colony. 

5.  Entomology.  —  The  establishment  of  a  strong  entomo- 

logical department  to  study  the  breeding-places  of 
mosquitos. 

6.  Anti  -  larval  laws.  —  In     1907    regulations   were   made 

against  stagnant  water  and  larvae,  enforcing  the 
screening  or  oiling  or  fish  stocking  of  stagnant 
water  which  could  not  be  got  rid  of 
In  1909  a  new  Draft  Ordinance  was  prepared  strengthen- 
ing these  regulations,  and  numerous  fines  have  been 
inflicted  for  contravention  of  the  Mosquito  Bye-laws. 

British  Guiana. — Population,  278,328.    Capital,  George  Town. 
Colony  intersected  by  innumerable  water  trenches,  swamps 
and  canals. 

Malaria,  the  principal  disease  of  the  colony. 
In  1907  the  deaths  from  malaria  were  301. 
Prophylaxis : — 

1.  Construction  of  good  roads  and  drains. 

2.  Pipe-borne  water-supply  to  George  Town  not  completed. 

3.  Fish  stocking  of  all  waterways. 


374  MALARIA   IN   THE  WEST   INDIES  [Sect. 

4.  Education,  and  training  of  sanitary  inspectors,  teachers, 

schools,  etc. 

5.  Sanitary  supervision,  removal  of  odd  water  receptacles. 

6.  Drainage    Ordinance.  —  In    1907    Bye-laws   were   intro- 

duced enforcing  proper  drainage  in  George  Town  ; 
later  these  were  extended  to  the  country  districts. 
Vat  Screening. — In  1907  an  Ordinance  was  introduced 
to  render  compulsory  the  screening  of  vats,  and  this 
law  was  enforced  in   1909. 

7.  The  distribution  of  quinine. 

Barbados. — Population,  199,542.     Chief  town,  Bridgetown. 

It  is  stated  on  good  authority  that  there  are  no  Anophelines 
present  in  this  island. 

Malaria  is  not  endemic ;  imported  cases  of  malaria  are 
common  amongst  the  labourers  returning  from  Panama.  The 
absence  of  Anophelines  is  attributed  to  the  very  porous  nature 
of  the  soil  throughout  the  island,  which  prevents  the  formation 
of  puddles.  The  ponds  which  are  met  with  are  all  apparently 
stocked  with  "  millions." 

In  Bridgetown  the  streets  are  well  drained  and  kept  flushed. 

Water-supply.  —  An  abundant  and  excellent  pipe-borne 
water-supply  was  introduced  into  the  colony  many  years  ago, 
and  has  since  been  extended.  It  strikes  at  the  root  of  endemic 
yellow  fever  by  putting  an  end  to  the  innumerable  odd  water 
receptacles  which  were  everywhere  abundant. 

In  1909  a  vigorous  anti-mosquito  compaign  was  started, 
and  the  Anti-stagnant  Water  Ordinance  of  1909  was  rigorously 
enforced. 

Sanitary  inspection  was  increased,  and  a  general  cleansing 
and  removal  of  all  odd  water  receptacles  carried  out. 

The  Bahamas. — In  1905  measures  were  adopted  against 
mosquito-carried  diseases,  and  in  1907  anti-larval  regulations 
were  enacted,  and  screening,  oiling  or  fish  stocking  of  stagnant 
water  enforced.     Quinine  was  also  distributed. 


44]  JAMAICA,    BRITISH    HONDURAS  375 

The  Northern  Islands. — In  1904  vigorous  action  was  com- 
menced against  mosquitos. 

Jamaica. — Population,  639,491.     Capital,  Kingstown. 

Anti-malarial  measures  in  Jamaica. — In  October  1909  a 
special  commission  was  appointed  to  investigate  and  to  take 
measures  to  remedy  the  conditions  which  gave  rise  to  malarial 
fever  in  different  parts  of  the  island  of  Jamaica.  The  Com- 
mission consisted  of  the  Colonial  Secretary,  P.  C.  Cork,  Arch- 
bishop Nuttall,  the  Superintending  Medical  Officer,  Dr  Kerr, 
Dr  Turton  and  Dr  Graham,  and  Messrs  Gideon  and  Hart. 
Mr  Isaacs  was  made  Official  Secretary  of  the  Commission. 

The  objects  of  the  Commission  were  to  ascertain  the  breed- 
ing-places of  Anophelines,  and  to  suggest  the  carrying  out  of 
remedial  and  preventive  measures ;  also  to  conduct  investiga- 
tions and  to  take  evidence  if  necessary.  The  Commission  had 
power  to  expend  up  to  ;^500. 

British  Honduras.  —  Chief  town,  Belize  ;  country  very 
swampy. 

Prophylaxis  : — 

1.  Anti-mosquito  work  was  commenced  in   1905,  and  has 

been  kept  up  with  marked  success. 

2.  A  mosquito  destruction  Ordinance  was  passed  in  1906. 

Owners  of  property  were   compelled  to  screen,  oil 
or  stock  with  fish  all  collections  of  water. 

3.  Drainage    and    filling  -  in    operations    have    also   been 

started. 
Bush  clearing  was  enforced. 


By  W.  T.  PROUT,  M.B.,  C.M.G. 

Lately  P.M.O.  Sierra  Leone 

45.  Malaria  in  Jamaica.— The  chief  factors  which  influence 
the  prevalence  and  distribution  of  malaria  in  Jamaica  are,  first, 
the  physical  configuration  of  the  island,  and  second,  the  methods 
of  cultivation,  which  are  necessitated  by  the  requirements  of  its 
forms  of  agriculture. 

The  centre  of  the  island  is  occupied  by  a  lofty  chain  of 
mountains  trending  generally  east  and  west,  from  which  spurs 
are  thrown  off  running  north  and  south,  with  intermediate  fertile 
valleys  :  while  the  coast  is  occupied  by  flat  alluvial  land  of  vary- 
ing extent.  From  the  mountains  a  number  of  streams,  some  of 
considerable  size,  rush  precipitously  down  till  they  reach  the 
lower  plains,  where  they  frequently  form  extensive  grass-grown 
swamps  and  open  into  the  sea  by  a  series  of  shallow,  sluggish 
mouths,  in  all  of  which  malaria-carrying  mosquitos  breed  in 
great  abundance. 

Moreover,  it  is  naturally  in  the  alluvial  plains  that  the  staple 
industries  of  the  island,  namely,  banana  and  sugar  plantations, 
are  carried  on.  In  the  north-eastern  portion,  where  the  land  is 
almost  entirely  under  banana  cultivation,  there  is  a  heavy  rain- 
fall, and  the  soil  is  stiff"  and  clayey.     In  consequence,  the  banana 


Sect.  45]  MORTALITY  AND   MORBIDITY  377 

plantations  have  to  be  deeply  trenched  for  the  purpose  of  subsoil 
drainage,  and  the  trenches,  unless  properly  graded  and  kept 
clear  of  grass  and  weeds,  afford  suitable  breeding-grounds  for 
Anophelines. 

In  the  south  and  south-eastern  parts  of  the  island  different 
conditions  obtain.  The  rainfall  is  small,  and  irrigation,  both  on 
banana  and  sugar  estates,  is  imperative.  Here  again  the  canals, 
unless  properly  supervised,  are  a  prolific  source  of  mosquitos. 

Among  minor  factors  may  be  mentioned  the  ponds  formed 
by  surface  drainage,  invariably  grass-grown,  and  used  sometimes 
as  the  water-supply  of  a  village,  and  more  frequently  as  cattle 
ponds  ;  and  the  shallow,  earthen,  weed-covered  gutters  along  the 
sides  of  the  streets  of  the  villages  and  towns. 

General  malarial  death-  and  sick-rates. — Although  the  exten- 
sive prevalence  of  malaria  in  certain  districts  of  Jamaica  has 
long  been  recognised,  and  its  seriousness  as  affecting  not  only 
the  general  health  and  the  death-rate  of  the  community,  but 
the  agricultural  development  of  the  colony,  was  fully  appreci- 
ated by  the  medical  profession,  yet,  apparently  from  the  apathy 
of  the  laity,  no  attempt  appears  to  have  been  made  to  make  an 
accurate  malarial  survey  of  the  island,  and  preventive  measures 
were  practically  non-existent.  In  the  latter  part  of  1908,  how- 
ever, an  expedition  from  the  School  of  Tropical  Medicine  of 
Liverpool  visited  the  island,  and,  thanks  to  the  active  co-opera- 
tion of  the  Government  and  of  the  Island  Medical  Service,  a 
systematic  though  limited  survey  was  made,  and  much  useful 
information  was  obtained.  The  following  statistics  are  mainly 
taken  from  one  of  the  reports  of  the  expedition  by  myself 
{Ann.  Trop.  Med.  Ill,,  No.  4,  17th  November  1909). 

The  total  malarial  deaths  for  the  whole  island  for  a  period  of 
ten  years  amounted  to  34,695,  which  is  equivalent  to  a  malarial 
death-rate  of  4*4  per  1,000.  The  general  death-rate  during  the 
same  period  was  22*5.  The  average  percentage  of  malarial  to 
total  deaths  was  197,  representing  nearly  one-fifth  of  the  total 
deaths. 


378 


MALARIA   IN   JAMAICA 


[Sect. 


A  summary  of  the  statistics  is  given  in  the  following  table  :- 


AVERAGE 

DEATH-RATES, 

ETC.,   FOR  THE   DECENNIUM 

ENDING 

30TH  APRIL   1907. 

Average  death- 

Average  death- 

Average  death- 

Average  percent- 
age of  malarial 
deaths  to 
total  deaths. 

Parish. 

rate  from 

rate  from 

rate  from 

malaria. 

other  causes. 

all  causes. 

St  Thomas    . 

6-5 

i8-5 

25*0 

26-1 

St  Catherine 

6-2 

19-4 

25-6 

24-4 

Westmorland 

5-9 

15-8 

217 

277 

St  Mary 

5-9 

i8-o 

23-9 

24-6 

Clarendon     . 

5*3 

15-2 

20'5 

23-8 

Portland 

5-3 

19-3 

24-6 

2 1 '9 

St  James 

4-8 

17-1 

21*9 

22-3 

Hanover 

4-8 

19-5 

24-3 

19-9 

St  Andrew    . 

4-0 

23-9 

27-9 

i4'6 

St  Ann  . 

3-4 

14-5 

17-9 

19-4 

Trelawny 

3'4 

20-8 

24-2 

14-4 

St  Elizabeth 

2-9 

15-6 

i8-5 

15-8 

Kingston 

2-4 

26*3 

287 

8-6 

Manchester  . 

1-6 

14-8 

i6"4 

I0"0 

Whole  island  . 

4*4 

i8-i 

22-5 

197 

But  the  prevalence  of  malaria  is  really  much  greater  than  is 
indicated  by  the  death-rate,  for  of  the  admissions  to  the  Govern- 
ment hospitals  of  the  colony,  it  is  found  that  at  least  one-third 
are  due  to  malaria,  and  the  malarial  sick-rate  shows  a  marked 
increase  of  recent  years. 


Year. 

Total  admis- 
sions from 
all  causes. 

Total 
deaths. 

Death- 
rate 
per 
cent. 

Malarial 
admissions. 

Malar- 
ial 
deaths. 

Malarial 
death- 
rate 
per  cent. 

Percentage 

of  malarial 

to  total 
admissions. 

1904-05 
1 905-06 
1906-07 
1907-08 

16,103 
17,856 
21,555 
21,837 

669 

563 
661 
830 

37 
31 
3-06 

3-8 

4,827 
6,285 
7,113 
7,510 

89 
88 

99 
121 

1-8 
1-4 
1-3 
1-6 

29-9 

35-1 
32-9 

34-3 

Total    . 

77,351 

2,723 

... 

25,735 

397 

Average 

19,337 

680 

3-5 

6,433 

99 

1-5 

33-2 

45]  COST   AND    SPLEEN-RATES  379 

It  is  calculated  that  the  cost  of  the  maintenance  and  treat- 
ment of  the  malarial  cases  alone  amounts  to  over  j£6,^oo 
per  annum. 

On  banana  and  sugar  estates  the  loss  of  time  through  illness, 
mainly  malarial  and  therefore  preventable,  amounted  to  sixteen 
out  of  every  hundred  working  days,  per  coolie  labourer  employed  ; 
while  among  the  constabulary,  a  picked  body  of  men,  it  is 
estimated  that  there  is  a  loss  of  nearly  four  thousand  days' 
service  per  annum  from  the  same  cause. 

T/ie  spleen  rate. — That  the  endemic  index  of  the  island  is 
high  is  shown  by  the  results  of  the  examination  of  the  spleens 
of  children.  Among  2,036  children  examined  in  all  parts  of  the 
island,  536  were  found  to  have  enlarged  spleens,  a  spleen  rate 
of  263^.  But  if  the  mountainous  centre  of  the  island  were 
to  be  excluded,  and  places  on  the  littoral  only  taken,  the  spleen 
rate  would  be  found  to  be  much  higher,  and  in  certain  localities 
rises  as  high  as  80%.  The  following  table  summarises  the 
results  of  the  splenic  survey : — 


No  of 

Spleens.^ 

Total  No. 

Average 
spleen. 

Parish. 

children 
examined. 

I 

3 

6 

9 

of  enlarged  ,     ^^^^ 
spleens. 

1 

Portland     .     . 
St  Mary      .     . 
St  Thomas 
St  Catherine   . 
St  Elizabeth    . 
Kingston     .     . 
Westmorland . 
Trelawny    .     . 
St  Ann  .     .     . 
Manchester     . 
Chapelton  .     . 

291 

398 

44 

212 

249 
220 

278 

189 

69 

42 
44 

112 

216 

27 

156 

195 
197 

255 

187 

69 

42 

44 

152 

158 

10 

48 

47 

23 

17 

2 

0 

0 

0 

26 

'72 

'I 

7 
7 
0 

5 
0 
0 
0 
0 

I 

I 
I 

0 
0 
I 
0 
0 
0 
0 

179 
182 
17 
56 
54 
23 
23 

0 
0 
0 

61-5 

457 

38-5 

26-4 

21.2 

10-4 

8-2 

ro6 

0 

0 

0 

2-5 
2-1 
2-3 

1-6 
i'5 

1-2 

r2 

1-03 

ro 

ro 

ro 

Total  . 

2,036 

1,500 

457 

73 

6 

536 

26-3 

12 

A  complete  splenic  survey,  in  order  to  obtain  an  accurate 
idea  of  the  distribution  of  malaria,  is  one  of  the  first  steps  to 
be  taken  in  any  anti-malarial  scheme. 

1  See  section  31  (4). 


38o  MALARIA   IN   JAMAICA  [Sect. 

Anti -  malarial  measures. — To  diminish  this  extensive  pre- 
valence of  malaria  the  following  measures  have  been  recom- 
mended as  being  particularly  applicable  to  the  requirements 
of  Jamaica : — 

1.  To    make  the  harbouring  of  mosquito  larvae  in  com- 

pounds a  punishable  offence. 

2.  To  keep  all  margins  of  rivers  and  swamps  in  the  neigh- 

bourhood of  towns  free  from  grass  and  weeds. 

3.  The  application  of  crude  kerosene  where  possible. 

4.  The  screening  of  wells,  tanks,  etc. 

5.  The  cementing  of  gutters  in  towns. 

6.  The  gradual  reclamation  of  swamps. 

7.  Screening  of  public  hospitals,  police  stations  and  coolie 

barracks, 

8.  Prophylactic  administration  of  quinine  to  police,  coolies, 

school  children  and  the  general  public. 

9.  Education  in  sanitation  and  hygiene,  all  of  which  would 

be  under  the  supervision  of  a  central  anti-malarial 
organisation. 

As  already  stated,  up  to  the  beginning  of  1909  little  in 
this  direction  has  been  done.  Small  quantities  of  quinine  had 
been  distributed  to  estates  for  prophylactic  purposes,  but  had 
not  been  given  systematically  and  continuously ;  a  few  isolated 
efforts  at  swamp  reclamation  had  been  made  by  private 
individuals,  and  one  police  station  had  been  made  mosquito- 
proof,  but  there  was  no  concerted  or  systematic  effort  to  stamp 
out  malaria. 

As  a  result,  however,  of  the  attention  which  was  drawn 
to  the  subject  by  the  expedition  from  the  Liverpool  School, 
probably  assisted  by  a  severe  outbreak  of  malaria  which  occurred 
in  the  spring  of  1909,  public  interest  appears  to  have  been 
awakened,  and  in  the  autumn  of  that  year  the  first  steps  were 
taken  to  deal  with  the  disease  in  an  organised  and  systematic 
manner.  His  Excellency  the  Governor  appointed  a  Com- 
mission, consisting  of  the  Colonial  Secretary,  the  Archbishop 


45]  MEASURES   ADOPTED  381 

of  the  West  Indies,  the  Chief  Medical  Officer,  and  other  medical 
men,  to  enquire  into  the  subject,  and  to  take  such  steps  as 
appeared  to  be  urgently  necessary.  A  series  of  public  lectures 
have  been  given,  which  has  done  much  to  spread  a  knowledge 
of  the  disease  in  different  parts  of  the  island  ;  a  new  Public 
Health  Ordinance  has  been  passed  ;  steps  have  been  taken  to 
train  sanitary  inspectors  in  the  recognition  of  the  breeding- 
places  of  Anophelines,  and  in  anti-mosquito  measures ;  and, 
most  important  of  all,  in  February  19 10  a  sum  of  ^^"5,000  was 
voted  to  carry  out  the  various  measures  necessary.  So  that 
now  we  may  consider  that  the  anti  -  malarial  campaign  in 
Jamaica  has  been  fully  started,  and  the  outlook  for  the  gradual 
extinction  of  malaria  in  the  island  is  distinctly  hopeful. 


By   H.    WOLFERSTAN   THOMAS,   M.D,   CM.   (M'GiLL) 

Of  the  Liverpool  School  of  Tropical  Medicine  Research  Laboratories, 
Manaos,  North  Brazil 

46.  Malaria  in  the  Amazon  Regrion,  and  the  Protection 
of  Ships. — (i).  Malaria  prevails  throughout  the  Aiiiaao?i  region. 
The  chief  industry  of  this  part  of  South  America  is  rubber, 
and  the  immense  trade  requires  a  large  number  of  men  to 
collect  the  crop.  The  conditions  under  which  they  work  cause 
many  privations  and  expose  them  to  infection.  The  old  say- 
ing that  every  kilo,  of  rubber  represents  the  loss  of  a  life  is  an 
exaggeration  but  there  is  an  enormous  mortality  amongst  the 
"  caucheros "  who  work  in  the  interior. 

In  the  vast  territory  watered  by  the  Amazon  River  three 
places  of  importance  occur,  which  serve  as  the  commercial 
centres  for  the  up-river  traffic  of  the  interior.  Iquitos,  2,200 
miles  from  the  mouth  of  the  Amazon,  is  the  only  large  town  in 
Peru  on  the  eastern  side  of  the  Andes.  Manaos,  on  the  Rio 
Negro,  some  900  miles  distant  from  the  mouth  of  the  Amazon 
River,  and  Para,  which  lies  near  the  mouth,  are  in  Brazil,  and 
possess  the  only  hospitals  for  the  accommodation  of  the 
up-river  patients.  No  attempts  have  been  made  by  the  states 
of  Amazonas  and  Para  to  create  any  hospitals  along  the  rivers 
in  the  interior  of  the  rubber  districts.  They  are  very  necessary, 
but  their  establishment  is  hindered  by  reason  of  the  enormous 
expenses  involved. 

Iquitos  has  no  pipe-borne  water-supply,  and  the  drainage  is 
of  the  most  primitive  character.  Extensive  swamps  extend  in 
and  about  the  town,  but  no  attempt  has  been  made  to  fill  them. 

382 


Sect.  46]  MANAOS  383 

Cellia  albimana  ^  and  Cellia  argyrotarsis  abound.  The  majority 
of  the  cases  appear  to  have  contracted  malaria  up-river. 

The  cities  of  Manaos  and  Para  receive  many  cases  of  malaria 
from  the  interior,  and  consequently  their  death-rates  are  unduly 
high.  Both  cities  suffer  from  the  return  of  the  infected  rubber- 
collectors,  who  go  and  live  in  the  suburbs  along  the  swamps ; 
they  either  neglect  all  treatment,  or  take  an  insufficient  amount 
of  quinine,  and,  living  in  a  state  of  poverty  and  misery,  they  lie 
in  their  mud  huts  exposed  to  the  bites  of  numerous  mosquitos. 
Their  blood  contains  many  gametes,  and  they  therefore  serve 
as  infecting  agents  for  the  Anophelines  that  feed  on  them. 
Their  presence  is  a  menace  to  the  community,  as  they  may 
cause  most  virulent  epidemics  of  malignant  types  of  the  disease. 

Manaos  is  intersected  by  many  creeks  and  swamps.  Those 
in  the  centre  of  the  city  are  completely  filled  ;  but,  on  the 
outskirts  of  the  city  proper,  certain  creeks  and  swampy  areas 
still  form  foci  of  malaria.  In  the  suburbs  extensive  swamps 
exist,  and  very  severe  forms  of  malaria  prevail.  A  modern 
system  of  drainage  and  water-supply  exists,  and  has  done  much 
to  mitigate  the  evils. 

COMPARISON  OF  MALARIA  INDEX  OF  CHILDREN   IN   SUBURBS  AND  CITY  ^ 


Swamps    r  Apparently  healthy 

in        \    Ailing 
Suburbs    \_  Average  both  classes 
City  swamps        .... 
Children  living  along  swamps  \ 

in  suburbs    .         .         .         . j 
Children  living  along  swamps  \ 

on  outskirts  of  city       .         .  J 


Spleen-rate. 


0-5  years. 


36-23 
46-82 

43  "o? 
12-94 


5-10  years. 


4274 

45-83 
44'36 
35-86 


43-82 
24-85 


Blood-rate. 


0-5  years. 


48-93 
51-80 
50-61 
29-23 


5-10  years. 


50-00 

57-14 
52-60 
48-78 


51-64 


40-13 


1  Newstead,  R.,  and  Thomas,  H.  Wolferstan  :  "  The  Mosquitos  of  the  Amazon 
Region,"  v^Mwa/j  Trop.  Med.  and  Parasitology,  vol.  iv.  No.  i. 

"  Thomas,  H.  Wolferstan:  "The  Sanitary  Conditions  and  Diseases  prevailing 
in  Manaos,  North  Brazil,  1905-1909,"  Annals  Trop.  Med.  and  Parasitology,  vol. 
iv.  No.  I. 


384  MALARIA  IN   THE  AMAZON   REGION  [Sect. 

The  state  and  municipal  authorities  are  gradually  destroying 
the  Anopheline  breeding-places  within  the  city.  Free  advice 
and  medicines  are  given  to  the  poor,  but  no  steps  have  been 
taken  to  organise  a  campaign  against  the  hordes  of  Cel.  albiinana 
and  argyroiarsis,  which,  especially  the  former,  are  the  carriers  of 
malaria  throughout  the  whole  of  the  Amazon  region. 

At  Porto  Velho  on  the  Madeira  River,  a  railway  is  being 
constructed  to  connect  Bolivia  and  Brazil.  Several  attempts 
have  been  made  to  build  this  line,  and  each  time  malaria  has 
raged  amongst  the  workmen.  A  most  virulent  form  of  fever 
occurs  which  has  at  times  incapacitated  50%  to  80^  of  the 
total  working  force.  The  difficulties  in  combatting  the  disease 
are  great,  and  are  increased  by  the  possibilities  of  importing 
yellow  fever  from  Manaos,  Serpa  or  Pard.  The  line  is  in  the 
interior,  through  virgin  forests  and  large  swamps  ;  an  organised 
attack  on  the  lines  of  the  anti-mosquito  campaign  of  Panama 
and  Xerem  in  South  Brazil  would  facilitate  the  progress  of  the 
undertaking.  A  graphic  account  of  some  of  the  past  unsuccess- 
ful attempts  is  recorded  by  Craig.^ 

Belem  or  Para  possesses  a  pipe-borne  water-supply.  The 
swamps  are  numerous  above  the  outskirts  of  the  city.  In  1909 
the  authorities  were  influenced  to  undertake  the  filling  of  much 
swampy  land,  and  to  institute  free  distribution  of  quinine.  A 
most  serious  outbreak  of  malaria  occurred  amongst  the  poorer 
inhabitants  living  in  the  outskirts  of  the  city,  along  the  swamps 
of  the  Marco  de  Legua,  Pedreira  and  Canudos,  etc.  A  medical 
commission  ^  traced  the  outbreak  to  the  arrival  in  Para  of  many 
labourers  who  had  returned  in  an  infected  condition  from  the 
Madeira-Mamore  railway  and  Alcoboca  works.  These  people 
went  to  the  outskirts,  and,  living  in  a  state  of  squalor,  they 
remained  untreated,  and  quickly  infected  the  numerous  Ano- 
phelines  of  the  locality.     Practically  every  one  in  the  district 

1  Craig,  Neville  B.  :  "  Recollections  of  an  Ill-fated  Expedition  to  the  Head- waters 
of  the  Madeira  River  in  Brazil."     (Lippencott. ) 

-  Relatorio  apresentado  pala  commissao  nomeada  para  debellar  a  epidemia  de 
pialmudismo,  reinante  no  Marco  de  Legua,  Pedreira  e  Canudos.  Belem.  Imprensa 
official  do  Estado  do  Para,  1909. 


46]  PARA  385 

suffered  from  malaria.  Free  clinics  were  opened,  and  in  four 
months  nearly  13,000  people  were  treated  with  quinine;  the 
very  severe  cases  were  sent  to  the  hospital.  Endeavours  were 
made  to  have  all  patients  with  enlarged  spleens  confined  in 
the  hospitals,  or  screened  from  mosquitos.  Mosquito-nets  were 
lent  and  all  gametocyte  carriers  were  energetically  treated  with 
quinine.  A  brigade  was  formed  to  fumigate  the  dwellings  of 
badly-infected  individuals,  and  a  general  purgation  of  the  sur- 
rounding yards  and  houses  was  made.  Measures  were  taken 
to  drain  and  fill  the  pools  and  swamps  of  the  most  heavily 
infected  districts,  and  as  many  breeding-places  as  possible  were 
destroyed.  A  great  and  general  improvement  was  noted  after 
a  few  months.  The  number  of  infections  and  the  number  of 
Anophelines  diminished,  and  it  is  to  be  hoped  that  these  satis- 
factory results  will  encourage  the  authorities  to  continue  their 
efforts.  The  expenses  were  about  ^9,500,  which  was  expended 
on  clinics,  hospital  accommodation,  drugs,  draining  and  filling 
of  pools,  swamps,  etc. 

The  inhabitants  of  the  Amazon  region  take  very  little  care 
to  avoid  contracting  malaria.  They  frequently  neglect  to  take 
quinine,  or  discontinue  it  after  a  few  days  of  treatment.  The 
labouring-class  Brazilian  hardly  ever  uses  a  mosquito-net,  and, 
unfortunately,  Europeans  are  prone  to  follow  their  example.  In 
Iquitos,  the  Peruvian  labourer  generally  protects  his  bed,  not 
because  of  malaria,  but  for  relief  from  the  swarms  of  Mansonia 
titillans  and  Culex  fatigans,  which  are  veritable  pests  ;  this  helps 
to  account  for  the  less  pronounced  infection  of  the  Peruvian. 

All  through  the  Amazon  region,  where  large  engineering 
works  have  been  undertaken,  the  old  familiar  story  has  been 
repeated.  Not  only  has  money  been  wasted,  but  many  lives 
have  been  sacrificed  by  the  neglect  of  the  promoters  to  realise 
the  dangers  of  malaria  and  Anophelines.  The  astute  commercial 
man  has  still  to  learn  that  it  is  cheaper  as  well  as  quicker  to 
organise  a  scientific  force  to  combat  malaria  or  yellow  fever,  and 
to  have  such  a  force  in  operation  before  any  attempt  is  made 

2  B 


386  MALARIA   IN  THE  AMAZON   REGION  [Sect 

to  import  labourers  and  commence  the  work.  The  Federal 
authorities  insert  clauses  regarding  quinine  prophylaxis,  screen- 
incr,  etc.,  in  the  contracts  with  the  concessionaires,  but  these 
clauses  are  frequently  neglected.  Many  important  engineering 
works  are  certain  to  be  undertaken  in  the  opening  up  of  the 
country  in  North  Brazil,  and  an  endeavour  should  be  made  to 
prevent  the  serious  loss  of  life  which  has  hitherto  occurred.  The 
sanitary  authorities  of  both  the  Amazon  and  Pard  states  are 
alive  to  the  necessity  of  combatting  the  disease  by  extermina- 
tion of  the  Anophelines. 

(2).  Protection  of  ships. — Very  little  attention  has  been  devoted 
to  the  protection  of  the  crew  and  passengers  of  steamers  navi- 
gating regions  where  malaria  prevails.  On  some  steamers 
mosquito-nets  have  been  provided  for  the  bunks,  and  a  few 
wire-screened  doors  for  the  outside  cabins,  wheel-house  and 
chart-room.  These  are  inadequate,  as  they  do  not  protect  the 
entire  living  quarters  of  the  passengers  and  crew. 

The  screening  of  a  steamer  is  a  difficult  undertaking.  Four 
facts  must  always  be  remembered. 

(i)  That  the  navigation  and  working  of  the  ship  should  not 
be  interfered  with. 

(2)  That  the  scheme  of  screening   shall  be  as  simple  as 

possible.  Elaborate  designs  are  certain  to  fail,  as 
they  cause  much  trouble  and  inconvenience  to  those 
on  board.  The  members  of  a  crew  or  even 
passengers  will  neglect  to  carry  out  complicated 
methods  of  closing  doors  and  port-holes. 

(3)  That  the  maximum  amount  of  air  shall  be  available.     In 

the  tropics  the  closeness  of  the  atmosphere  does 
not  encourage  the  average  individual  to  reduce  the 
ventilation  by  the  interposition  of  wire-gauze  screens. 
I  have  seen  on  a  steamer  plying  to  the  Pacific  large 
screened  wooden  frames,  designed  to  fit  in  the  port- 
holes, but  so  massively  constructed  that  the  cross 
diameter  was  reduced  nearly  one-half     It  is  hardly 


46]  PROTECTION    OF   SHIPS  387 

to  be  expected,  since  so  much  air  and  light  is  cut 
off,  that  the  crew  will  make  use  of  the  screens. 
(4)  That  an  endeavour  should  be  made  to  screen  the  vessel 
in  sections,  so  that  if  mosquitos  succeed  in  obtaining 
an  entry,  they  can  only  circulate  in  that  part  of  the 
ship  and  can  be  hunted  down  and  destroyed, 

Mosquitos  generally  board  a  ship  when  it  is  moored  near  the 
shore  or  is  hugging  the  banks,  and  they  quickly  find  their  way 
to  the  saloons  and  living  quarters  of  the  crew. 

All  parts  of  a  ship  which  communicate  with  the  danger  zone, 
i.e.y  the  open  deck,  should  be  protected.  The  doors  should  be 
screened,  and  where  there  is  much  passing  to  and  fro  between 
a  protected  area  and  the  danger  zone,  a  second  door  should  be 
placed  some  3  or  4  feet  away,  thus  forming  a  vestibule,  and 
allowing  one  door  to  be  closed  before  the  other  is  opened.  All 
doors  should  be  provided  with  spring-locks  which  catch  easily, 
and  a  strong  door-spring  to  ensure  a  rapid  and  tight  closing  of 
the  door.  If  the  storm-doors  are  left  on,  care  should  be  taken 
that  the  knobs  do  not  impinge  upon  the  wire  screens  and  so 
tear  or  fray  the  gauze. 

The  ventilators  leading  to  the  cabin,  alleyways,  etc.,  should 
be  screened  at  the  ceiling  vent. 

Through  the  courtesy  of  the  Booth  Steamship  Company 
the  plans  of  a  vessel  specially  screened  against  mosquitos  are 
shown.  The  ship  is  designed  for  use  in  ocean  and  river-trade,  in 
a  district  severely  infected  with  malaria  and  Anophelines.  The 
port  of  call  is  far  up-river,  and  is  notorious  for  the  severity  of 
the  malarial  infection.  It  is  the  outcome  of  the  experience 
gained  by  Dr  Melville  Davidson,  Medical  Superintendent  of 
the  Company,  to  whom  I  acknowledge  my  indebtedness. 

All  the  port-holes  of  the  steamer  are  provided  with  removable 
screened  frames,  which  are  so  adapted  that  the  port-hole  can  be 
closed  and  screwed  down  without  necessitating  the  withdrawal 
of  the  screens.  The  frame  of  the  screen  consists  of  a  metal 
hoop,  on  which  gauze  is  tightly  stretched  and  soldered,     The 


388  MALARIA   IN   THE   AMAZON    REGION  [Sect. 

frame  is  provided  with  rigid  bayonet  catches,  which  are  so 
arranged  that  they  sHp  easily  into  the  ordinary  port,  and  a 
half  turn  of  the  screen  is  sufficient  to  lock  it. 

All  the  ventilators,  as  is  seen  in  the  drawings  (figs.  1-4),  are 
screened  by  a  most  simple  and  efficient  arrangement.  Ordinary 
circular  moulding  is  fastened  on  the  ceiling  around  the  vent 
pipe ;  the  moulding  has  a  deep  groove,  into  which  fits  a  round 
metal  frame  covered  with  wire-gauze  ;  the  screened  frame  is 
retained  in  position  by  three  small  buttons,  so  that  it  can  be 
instantly  applied  or  removed. 

The  screen  doors  have  light  wooden  frames  and  panels  of 
wire-gauze.  They  are  provided  with  spring-locks  and  strong 
coiled  wire  door-springs. 

By  reference  to  the  accompanying  plan  (figs.  5,  6)  it  will  be 
seen  that  the  arrangement  of  the  screening  is  quite  simple  and 
yet  adequate.  The  screened  port-holes  and  doors  are  outlined 
in  black.  The  only  entrances  to  the  saloon,  chart-room,  captain's 
cabin,  pantry  and  bath-room,  are  through  a  screened  door  on  the 
port  side,  another  on  the  starboard  side,  and  a  third  at  the  foot 
of  the  stairs  leading  from  the  wheel-house.  The  outside  cabins 
are  all  shown  with  screened  doors  and  port-holes.  Further  aft, 
and  isolated  by  the  steam-steering  gear,  are  the  cabins  of  the 
doctor  and  hospital. 

On  the  main  deck  the  entrances  on  the  port  and  starboard 
sides  through  which  the  crew  must  pass  to  their  work  are 
screened.  On  the  starboard  side  there  are  two  sets  of  screened 
doors  along  the  alleyway.  These  are  provided  because  the  ash- 
discharger  is  open  to  mosquitos  and  therefore  constitutes  a 
danger  zone.  On  the  port  side  this  extra  screening  is  un- 
necessary, as  in  the  river  only  one  ash-shoot  will  be  used. 

A  study  of  the  plan  will  show  that  the  only  unscreened  parts 
of  the  ship  communicating  with  the  interior  are  the  engine-room, 
stoke-hole  and  galley.  Theoretically,  these  sections  should  be 
screened,  but  two  factors  must  be  taken  into  account,  viz.,  the 
intense  heat  of  the  places,  which  is  always  accentuated  in  the 


8.S.    "VINCENT." 

ON    OF   SHIP    SHEWING    MOSQUITO 
TION   TO   DOORS  AND   PORTS. 


-f  i:-H--  u^4s- 


Fi^.r 


TbFojce' Page.  388. 


SKETCH    SHEWING    MOSQUITO    PROTECTION    FOR 

DOORS,   VENTILATORS    AND    PORTS. 

S.S.    "VINCENT." 


•  « 


DOORS    AND    PORTS 


7V>  Voc»  Fbge  3/III. 


SKETCH    SHEWING    MOSQUITO    PROTECTION    FOR 

DOORS,   VENTILATORS    AND    PORTS. 

S.6.    "VINCENT." 


DOOR,  PORT  AND   VENTILATOR 


Fiq.3. 


FiAj.2. 


Method   of   »ttachin4    wire-gauil    sciiken   to    frames. 


DOORS    AND    PORTS. 


1^.4. 


ToFace'FkLge'388. 


6.S.    "VINCENT." 

PART    SECTION    OF    SHIP    SHEWING    MOSQUITO 
PROTECTION   TO    DOORS   AND   PORTS. 


Mg.1. 


To  Face  Page  3S8. 


BOAT      DECK 


•i  I  I      ,^r^ 


^^g^^ 1  ^  ^  I       "757 


"  '^Ts. m  f^  A.  ^ 


-Fig  5. 


POOP     s,      BRIDGE         DECK 


-f-i/G^ ^ 


Tc  Face  Page  3(t8. 


46]  PROTECTION    OF   SHIPS  389 

tropics,  and  the  coal-dust,  that  would  cake  and  block  the  meshes 
of  the  screen,  and  thus  restrict  the  inlet  of  air.  The  wheel- 
house  is  unprotected,  as  screening  would  be  impossible  when 
navigating  a  river. 

Provided  the  screening  is  not  disturbed  very  few  mosquitos 
should  be  able  to  gain  an  entry,  and  adequate  regulations  can  be 
made  to  prevent  such  acts  as  the  taking  off  of  a  port-hole  screen 
or  tying  back  a  door. 

For  port-holes  an  18  mesh  should  suffice,  and  the  gauge  of 
wire  need  not  be  thicker  than  32  or  30.  For  doors  which  are 
liable  to  be  roughly  used,  a  heavier  gauge  wire  is  necessary. 
The  mode  of  application  of  the  wire-gauze  is  important.  The 
gauze  should  not  be  tacked  on  to  the  frame.  A  far  better 
method  is  to  have  a  deep  groove  running  around  the  panel 
(fig.  3),  and  a  rod  either  of  wood  or  metal  of  a  size  slightly 
smaller  than  the  groove.  The  wire-gauze  is  laid  over  the  entire 
panel  and  the  rods  driven  into  the  grooves.  This  makes  the 
wire  taut  and  the  tension  is  equally  distributed.  All  strands  of 
the  mesh  are  fastened  securely,  which  is  not  the  case  with  gauze 
fastened  down  by  tacks.  Over  the  rod  a  neat  strip  of  moulding 
can  be  fixed,  which  finishes  off  the  panel  and  can  be  easily 
removed.  The  great  advantage  of  this  method  is  that  it  is  a 
comparatively  simple  matter  to  take  off  the  strip  of  moulding, 
remove  the  rods,  and  substitute  another  piece  of  gauze.  This 
method  is  extensively  used  all  through  the  United  States. 

Excellent  arrangements  for  large  private  yachts  and  even 
passenger  steamers  can  be  devised.  I  have  seen  nearly  the 
whole  of  the  bridge  deck  enclosed  with  ordinary  mosquito- 
netting.  The  top  was  made  of  tarpaulin  stretched  on  robes, 
and  the  sides  were  made  of  gauze.  At  sunset  the  sides  were 
let  down,  and  from  fifteen  to  thirty  people  were  able  to  dine  and 
sleep  in  comfort.  The  expense  is  not  so  great,  and  is  amply 
compensated  for  by  the  relief  from  mosquitos.^ 

^  Messrs  John   Holt   &   Co.    have    recently  screened   an    entire   ship   for  West 
Africa. — R.  Ross. 


46]  PROTECTION    OF    SHIPS  389 

tropics,  and  the  coal-dust,  that  would  cake  and  block  the  meshes 
of  the  screen,  and  thus  restrict  the  inlet  of  air.  The  wheel- 
house  is  unprotected,  as  screening  would  be  impossible  when 
navigating  a  river. 

Provided  the  screening  is  not  disturbed  very  few  mosquitos 
should  be  able  to  gain  an  entry,  and  adequate  regulations  can  be 
made  to  prevent  such  acts  as  the  taking  off  of  a  port-hole  screen 
or  tying  back  a  door. 

For  port-holes  an  18  mesh  should  suffice,  and  the  gauge  of 
wire  need  not  be  thicker  than  32  or  30.  For  doors  which  are 
liable  to  be  roughly  used,  a  heavier  gauge  wire  is  necessary. 
The  mode  of  application  of  the  wire-gauze  is  important.  The 
gauze  should  not  be  tacked  on  to  the  frame.  A  far  better 
method  is  to  have  a  deep  groove  running  around  the  panel 
(fig.  3),  and  a  rod  either  of  wood  or  metal  of  a  size  slightly 
smaller  than  the  groove.  The  wire-gauze  is  laid  over  the  entire 
panel  and  the  rods  driven  into  the  grooves.  This  makes  the 
wire  taut  and  the  tension  is  equally  distributed.  All  strands  of 
the  mesh  are  fastened  securely,  which  is  not  the  case  with  gauze 
fastened  down  by  tacks.  Over  the  rod  a  neat  strip  of  moulding 
can  be  fixed,  which  finishes  off  the  panel  and  can  be  easily 
removed.  The  great  advantage  of  this  method  is  that  it  is  a 
comparatively  simple  matter  to  take  off  the  strip  of  moulding, 
remove  the  rods,  and  substitute  another  piece  of  gauze.  This 
method  is  extensively  used  all  through  the  United  States. 

Excellent  arrangements  for  large  private  yachts  and  even 
passenger  steamers  can  be  devised.  I  have  seen  nearly  the 
whole  of  the  bridge  deck  enclosed  with  ordinary  mosquito- 
netting.  The  top  was  made  of  tarpaulin  stretched  on  robes, 
and  the  sides  were  made  of  gauze.  At  sunset  the  sides  were 
let  down,  and  from  fifteen  to  thirty  people  were  able  to  dine  and 
sleep  in  comfort.  The  expense  is  not  so  great,  and  is  amply 
compensated  for  by  the  relief  from  mosquitos.^ 

1  Messrs  John   Holt   &   Co.    have   recently  screened   an   entire   ship   for  West 
Africa. — R.  Ross. 


By  Dr  OSWALDO  GONgALVES  CRUZ 

Director  of  the  Institute  of  Manguinhos 

47.    Prophylaxis    of    Malaria    in    Central    and    Southern 

Brazil. — Several  anti-malarial  campaigns  have  been  carried  on 
under  the  technical  direction  of  our  Institute,  all  of  which  have 
been  crowned  with  the  most  complete  success.  They  were 
undertaken  in  the  following  chronological  order  : — 

(i)  In  the  construction  of  the  Itatinga  Railway,  Santos. 

(2)  In    the    work    of   damming    the    Rivers    Xerem    and 

Mantiquira,   for    the    water-supply   of    the    city   of 
Rio  de  Janeiro. 

(3)  At  the  time  of  the  extension  works  of  the  Brazilian 

and  Northern  of  Minas  Railway, 

(4)  During  the   survey  work   for  the   Bahia  and   Espirito 

Santo  Railway. 

(5)  During  the  construction  of  the  North  West  of  Brazil 

Railway. 

(6)  In  the  suburbs  of  the  city  of  Rio  de  Janeiro  in  con- 

nection with  the  prophylaxis  of  yellow  fever. 
The  most  important  campaigns  were  conducted  by  Drs 
Carlos  Chagas,  Arthur  Neiva  and  Gomes  de  Faria,  Members 
of  the  Institute;  and  Dr  Carlos  Chagas  (1906- 1907- 1908)  had 
already  written  on  some  of  them,  he  being  among  us  the  first 
to  organise  a  scientific  campaign  against  malaria. 

The  prophylactic   formulae  adopted  by  the  Institute  com- 
prised the  following  : — 

(i)  Prophylaxis  by  quinine  exclusively,  adopted  when  the 
treatment  had  to  be  applied  to  a  moving  population 
390 


Sect.  47]  QUININE  391 

and  one  not  remaining  any  length  of  time  in  a 
particular  zone  (railway  construction). 

(2)  Preventive  administration  of  quinine,  isolation  of  the 

persons  infected  with  gametes,  in  infirmaries  fitted 
with  wire-gauze,  and  unrelaxing  treatment  of  those 
infected.  This  system  was  adopted  when  the 
persons  already  infected  had  to  reside  for  some 
time  in  the  infected  zone  with  healthy  persons,  and 
where  the  work  was  done  more  slowly. 

(3)  The  same  measures  as  above,  together  with  systematic 

sulphur  disinfection  of  infected  dwellings.  Prophy- 
laxis adopted  when  the  staff  remained  for  a  longer 
period  in  the  infected  zone,  and  where  it  was  not 
possible  to  carry  out  prophylaxis  by  means  of 
larvicide. 

(4)  Indirect  prophylaxis  by  war  on  mosquitos. 

Let  us  see  more  in  detail  how  these  prophylactic  systems 
were  carried  out  among  us. 

The  first  prophylactic  formula. — This  was  put  into  execution 
with  success  in  the  surveys  for  the  South  of  Bahia  Railway, 
by  Drs  Mauricio  de  Abreu  and  F.  Soledade,  of  the  General 
Board  of  Public  Health.  The  process  consisted  in  the  daily 
administration  of  50  centigrammes  of  hydrochlorate  of  quinine. 
It  was  compulsory,  and  the  medicine  was  administered  by  the 
doctors  themselves,  who  saw  that  the  patients  swallowed  the 
capsule.  In  this  case,  as  the  persons  never  remained  long  in 
the  same  place,  the  dose  of  quinine  given  was  always  prophy- 
lactic, which  is  not  the  case  when  the  persons  remain  for  a  long 
time  in  the  same  infected  places,  as  we  shall  see  later.  In  the 
special  case,  the  results  were  most  complete  ;  not  one  of  the 
persons  subjected  to  the  regime  fell  sick,  whereas  others  who 
accompanied  the  party,  without  belonging  to  it,  and  who  would 
not  submit  to  the  same  prophylaxis,  were  attacked  by  malaria. 

The  second  prophylactic  formula. — Here  the  process  followed 
out  included  : — 


392     MALARIA  IN  CENTRAL  AND  SOUTHERN  BRAZIL     [SECT. 

(i)  The  preventive  administration  of  quinine,  in  the  dose 
of  50  centigrammes  every  three  days, 

(2)  The  isolation  of  the  persons  infected  with  gametes,  in 

infirmaries  protected  by  wire-gauze  during  the  hours 
the  Anopheles  sting,  being  subjected  to  strict  treat- 
ment until  the  gametes  disappear. 

(3)  Early  and   radical   treatment  of  persons   infected    for 

the  first  time  and  not  themselves  infectious  (this  was 
done  without  isolation),  in  order  to  prevent   them 
becoming  infectious  to  mosquitos  by  the  formation 
of  gametes. 
Dr  Neiva,  who  was  entrusted  with  the  carrying  out  of  the 
quinine  prophylaxis  on  a  large  scale  (among  some  3,500  work- 
men at  Xerem),  observed  that  among  those  treated  with  quinine 
cases  of  first  infection  began  to  appear  and  increase  rapidly. 
He  was  able  to  verify  these  positively  by  excluding  the  cases 
of  reappearance   noted   after  the  beginning  of  the  campaign. 
Satisfied  that  the  dose  of  quinine  was  not  sufficient  to  guarantee 
the  prophylaxis,  he  proceeded  to  administer  it  at  intervals  of 
two  days ;  after  some  time,  fresh  cases  of  first  infection  began  to 
appear,  and  these  were  only  really  stopped  when  he  commenced 
to  administer  the  quinine  in  a  daily  dose  of  50  centigrammes. 

It  is  interesting  to  note  that  among  the  persons  thus  treated 
with  quinine  an  outburst  of  malaria  occurred  when  they  dis- 
continued the  use  of  quinine,  even  though  the  practice  had 
been  continued  after  leaving  the  infectious  malarial  zone ;  and 
to  prevent  such  attacks  it  became  necessary  to  continue  the 
use  of  quinine  for  a  long  time,  and  repeat  treatment  at  intervals. 
Stranger  still,  persons  who,  after  leaving  the  malarial  zone, 
went  to  reside  in  places  which  were  certainly  not  infected, 
where  they  continued  the  use  of  the  quinine  (50  centigrammes 
daily)  for  a  month,  as  soon  as  they  abandoned  this  preventive 
were  attacked  by  malaria.  Such  persons  had  remained  for 
fourteen  months  in  the  infected  zone  without  ever  suffering 
any  attack  of  fever.     When  under  the  action  of  quinine  they 


47]  DESTRUCTION    OF   ADULTS  393 

had  no  fever,  but  harboured  plasmodia  in  the  system.  Dr 
Neiva,  in  view  of  his  observations,  admits  that  during  the 
quinine  prophylaxis  the  plasmodia  become  gradually  accustomed 
to  the  quinine  and  immune  against  t/it's  pot'son,  giving  rise  to  a 
family  able  to  resist  the  quinine,  and  similar  to  the  families  of 
trypanosoma  which  defy  atoxyl.  Subsequent  to  this  interest- 
ing observation  of  Dr  Neiva's  (made  in  October  1907)  several 
other  authors  have  referred  to  analogous  facts.^ 

The  occurrence  of  the  new  infections  could  not  be  attributed 
to  the  inefficient  administration  of  the  quinine.  This  was  com- 
pulsory, and  was  administered  by  trustworthy  persons,  the 
infections  being  found  to  exist  in  persons  who  undoubtedly 
had  taken  the  prescribed  doses. 

The  second  item  of  the  prophylactic  formula  under  con- 
sideration is  intended  to  destroy  the  gametes  in  circulation, 
which  prevents  the  infection  of  the  mosquitos,  which,  as  we 
know,  can  only  occur  when  there  are  gametes  in  the  periphery. 
This  result  was  obtained  by  the  daily  and  continuous  adminis- 
tration of  50  centigrammes  of  quinine.  It  was  proved  by 
the  microscope  that  after  a  time  it  was  no  longer  possible  to 
recognise  the  existence  of  gametes,  whether  of  the  benign  or 
of  the  malignant  (tropical)  tertian.  When  the  parthenogenesis 
of  the  gametes  occurred,  following  on  excessive  work  or  heavy 
rains,  i  gramme  of  quinine  was  given  daily,  as  a  rule  by 
intramuscular  injection.  It  should  be  noted  that  no  scabs 
appeared  after  the  injections. 

The  above  shows  the  necessity  of  carrying  on  the  anti- 
malarial campaigns  by  persons  capable  of  making  the  utmost 
use  of  the  assistance  furnished  in  such  cases  by  the  microscope. 

T/ie  third  prophylactic  formula. — Dr  Carlos  Chagas,  in  his 
studies  on  the  epidemiology  of  malaria,  and  on  the  biology 
of  the  Anopheles  responsible  for  the  transmission  of  the  trouble 
within  the  zones,  found  that  there  were  dwellings  constituting 
regular  hot-beds  of  malaria,  and  that  such  houses  were  invaded 

^  Incubation  retarded  by  quinine  is  well  known. — R.  Ross. 


Sect.  47]  DESTRUCTION   OF   LARVAE  395 

at  night  by  the  Anopheles,  which  stayed  there  till  dawn,  some 
withdrawing  to  the  woods,  whence  they  returned  the  following 
night,  others  remaining  concealed  in  the  dark  damp  places  of 
the  huts. 

These  infected  mosquitos  caused  the  permanently  infected 
condition  of  these  dwellings.  The  opinion  that  malaria  is  a 
disease  commonly  infectious  in  houses  finds  a  perfectly  feasible 
basis  in  arguments  relating  to  the  biology  of  the  Anopheles, 
and  in  numerous  facts  arising  from  careful  observation.  In 
view  of  this  Dr  Chagas  resolved  to  make  systematic  cleansing 
by  sulphur  vapours  in  such  dwellings,  and  thus  succeeded  in 
sterilising  these  centres  of  infection. 

These  measures  were  always  accompanied  by  quinine 
prophylaxis.  But  as  an  experiment  Dr  Chagas  ascertained 
that  the  treatment  of  dwellings  by  sulphur  was  sufficient  to 
prevent  the  infection  of  the  persons  who  passed  the  night  in 
such  deadly  centres  of  malaria,  and  who  were  not  subjected 
to  the  action  of  quinine. 

The  fourth  prophylactic  formula. — This  consists  of  indirect 
war  against  malaria  by  the  destruction  of  the  larvae  of  the 
Anopheles.  This  prophylactic  system  was  tested  at  Rio  de 
Janeiro,  when  the  prophylaxis  of  yellow  fever  was  carried  out 
in  the  metropolis  of  Brazil.  One  part  of  the  war  on  mosquitos 
was  begun  by  drying  up  all  temporary  deposits  of  water,  the 
destruction  of  the  larvae  in  natural  deposits  by  means  of 
the  cultivation  of  larvae  -  devouring  fish  {Girardinus  caudi- 
maculatus),  by  the  protection  of  indoor  water  -  cisterns  from 
mosquitos,  the  petrolising  of  large  sheets  of  water,  the  destruc- 
tion of  the  Bromelias  epiphytes,  etc. 

The  results  obtained  were  very  favourable,  as  may  be  seen 
by  an  examination  of  Table  No.  i,  which  we  give  below.  In 
Table  No.  2  is  given  the  complete  result  of  the  anti-yellow 
fever  campaign.  The  malaria  figures  do  not  show  the  same 
decrease  as  those  for  yellow  fever,  because  in  the  table  for 
malaria    the    cases    existing    in    the    urban   hospitals,   where 


396     MALARIA  IN  CENTRAL  AND  SOUTHERN  BRAZIL    [Sect. 

patients  were  received  from  rural  zones  not  influenced  by  the 
prophylactic  campaign,  appear. 


TABLE   II. 

TABLE   OF   MORTALITY    BY   YELLOW   FEVER    IN    RIO    DE   JANEIRO    FROM 

1872    TO    1909. 


1872 
1873 
1874 

1875 
1876 
1877 
1878 
1879 


1891 
1892 

1893 
1894 

1895 
1896 
1897 


1900 
1901 
1902 
1903 
1904 

1905 
1906 
1907 
1908 
1909 


16 

23 
122 

3 

156 

102 

138 

50 

3 

8 

79 

15 

201 

6 

30 

510 

57 

51 

1,006 

4 

371 

27 

524 
28 
22 
99 
42 
13 
32 

133 
2 

3 

6 


SI 
168 

319 

ID 

420 

227 

496 

67 

13 

9c 

208 

28 

351 
18 

39 
719 
103 

357 
1,290 

57 
1. 351 

41 
731 

33 

90 
170 

64 

41 

64 

142 

7 
13 

9 


953 
168 

385 
1,405 

74 
331 
226 

471 
46 

23 

335 

253 

58 

483 

89 

29 


281 

297 

301 

1,019 

35 
130 
169 

273 
26 
27 

598 

210 
51 

304 
37 

128 


539 

142 

187 

169 

1,026 

960 

1,404 

410 

108 

135 

1.978 

695 

86 

141 

1,002 

445 

37 

20 

255 

287 

204 

91 

78 

61 

69 

64 

16S 

178 

151 

99 

7 

8 

23 

59 

6 

8 

6 

14 

I 

165 

244 

395 
40 
60 
81 

"5 
25 
12 

300 
68 
65 
74 
18 

116 

97 
109 
600 

147 
172 

305 

104 

136 

17 


36 
37 
154 
24 
10 
64 


3 

83 

69 

104 

147 
12 

23 
54 
58 
14 
8 
III 
15 
57 
23 


61 

38 

421 

35 
141 
114 

77 

37 
6 

78 

25 
28 

17 

131 

10 

4 
61 
I 
4 
3 


37 

41 

4 

18 

43 
18 

13 

I 

69 

12 

44 
9 

I 

50 
27 
22 
190 
14 
73 
14 
51 
20 

3 
65 
II 

9 

14 

79 

9 

4 

26 


18 


16 


383 

I 

37 

7 

166 


102 

3.659 
829 

1,292 

3.476 
282 

1,176 

974 
1.625 

257 


863 
445 

1-449 
137 
747 

2,156 
719 

4.456 

4.312 
825 

4.852 

818 

2,929 

159 
1,078 

731 
344 
299 
984 

584 
48 

289 

42 

39 

4 


Table  No.  3  shows  the  results  obtained  in  the  campaign 
undertaken  at  the  time  of  the  damming  of  the  Rivers  Xerem 
and  Mantiquira  for  the  water-supply  of  the  city  of  Rio  de 
Janeiro.     The  region  through  which  canalisation  work  had  to 


47]  BRAZILIAN    ANOPHELINES  397 

be  extended  was  so  devastated  by  malaria  that  95^  of  the 
men  employed  in  the  work  were  attacked,  the  mortality  being 
so  heavy  that  the  Government  was  obliged  to  abandon  the 
first  attempt.  Work  could  not  be  resumed  until  the  special 
prophylactic  service  for  malaria  had  been  organised,  with  the 
result  that  in  a  few  months  the  works  were  completed  and 
the  city  of  Rio  de  Janeiro  provided  with  an  abundant  supply  of 
drinking  water. 

In  the  malarial  zones  of  Brazil  the  following  species  of 
Anopheles  are  found  : — Cydolepteron  mediopunctatuin  (Theob, 
Lutz),  Cydolepteron  interniedimn  (Chagas),  Cellia  argirotarsis 
(Theob),  Cellia  albiniana  (Wied),  and  Arribalzagaia  pseudoma- 
culipes  (Chagas). 

These  are  undoubtedly  the  transmitters  of  malaria,  as  was 
experimentally  shown  by  the  characteristic  forms  of  evolution 
of  the  Plasmodium  in  them. 

The  following  species  are  suspected  of  transmitting  the 
malaria,  so  far  as  can  be  judged  by  epidemiological  studies: — 
Myzomyia  lutzi  (Theob),  Cellia  braziliensis  (Chagas),  Myzorhyn- 
chella  lutzi  (Cruz),  Myzorhynchella  parva  (Chagas). 

As  to  the  habits  of  the  Anopheles,  Dr  Chagas  noticed  that 
as  a  rule  they  suck  only  at  certain  hours,  at  nightfall,  when 
they  come  in  swarms,  or  in  the  early  hours  of  the  morning. 
They  disappear  entirely  during  the  day  and  night,  at  which 
time,  therefore,  there  is  no  danger  of  men  being  infected  by  the 
contaminating  mosquitos,  or  of  the  mosquitos  being  infected 
by  sick  persons  with  gametes.  An  exception  to  this  rule  is 
the  Cellia  braziliensis  (Chagas),  which  attacks  for  preference 
during  the  day  and  in  the  sun,  which  fact  shows  the  necessity 
of  studying  the  Anopheles  fauna  of  the  region  in  which  it  is 
proposed  to  start  an  anti-malarial  campaign. 

Further  details  as  to  the  Brazilian  Anopheles  and  their 
relations  with  malaria  may  be  found  in  the  works  of  Dr  A. 
Neiva,  lately  published  (1909). 

In  dealing  with  the  organisation  of  the  systematic  prophy- 


398  MALARIA  IN  CENTRAL  AND  SOUTHERN  BRAZIL    [Sect.  47 

laxis  against  malaria  a  knowledge  of  the  existence  of  the 
Myzoniyia  lutzii  (Theob.)  in  the  region  is  deserving  of  special 
attention. 

This  mosquito,  which  appears  to  be  responsible  for  the 
transmission  of  malaria  in  the  regions  where  there  are  no 
swamps,  lives  in  the  waters  found  in  the  Bromelias  epiphytas 
(Lutz,  1902),  and  is  so  small  that  it  can  pass  through  the  wire- 
gauze  of  1*5  mm.  mesh,  usually  employed  for  protection  of 
houses.  For  this  further  reason  it  is  advisable  to  study  the 
Anopheles  fauna  of  the  region  before  proceeding  to  instal 
mechanical  prophylaxis  of  malaria. 

Finally,  it  should  be  mentioned  that  the  quinine  prophy- 
laxis has  been  carried  out  without  the  slightest  inconvenience 
to  the  persons  subjected  thereto^  there  being  a  large  number  of 
people  who  have  used  daily  50  centigrammes  of  hydrochlorate  of 
quinine  for  the  last  two  years  and  ten  months  without  showing 
the  slightest  bad  effect  from  the  employment  of  this  medicine. 
Further,  the  phenomena  of  noises  in  the  ears,  etc.,  are  not 
observed  when  the  quinine  is  administered  at  meal  times.  No 
cases  of  hoemoglobinuria  have  been  observed  following  on  the 
administration  of  the  quinine,  and  the  few  cases  (8)  of  this  morbid 
nature  observed  disappeared  with  the  quinine  treatment. 

BIBLIOGRAPHY 

1902.  Dr  Ad.  Lutz.— "  Forest  Mosquitos  and  Forest  Malaria."  Central- 
Blatt  ficr  Bakt.  etc.,  ist  pt.  orig.  vol.  xxxiii.  p.  282. 

1906-7.  Dr  Carlos  Chagas. — "  Prophylaxis  of  Malaria."  Brazil-medico, 
year  xx.  pp.  315-337  and  419  ;  year  xxi.  p.  151. 

1908.  Dr  Carlos  Chagas.— A  paper  on  "  Malarial  Prophylaxis."  Zeit- 
schrift  fiir  Hygiene  und  Insect  krank.  vol.  Ix.  p.  321. 

1908.  "  Prophylaxis  of  Malaria."     Paper  read  at  the  6th  Brazilian  Congress 

of  Medicine  and  Surgery.  In  Revista  Medica  de  Sao  Paulo., 
No.  19,  year  xi.  p.  391. 

1909.  Dr    Arthur    Neiva.—"  Contribution  to   the   Study    of    Diptera." 

Observations  on  the  biology  and  organism  of  Brazilian  Anopheles, 
and  their  relations  with  malaria.  Proceedings  of  the  Oswaldo 
Cruz  Institute,  vol.  i.  p.  69. 


Table  3. 


di^JiL-lWlli:ii..i.-^:^-- 


\To  face  page  398. 


By  IAN  MACDONALD,  M.D,  Edin,  M.D.,  Paris 

Huelva,  Spain 

48.  Malaria  in  Spain. — Among  the  countries  of  Europe, 
Spain  has  always  suffered  severely  from  malaria,  and  the 
records  of  history  show  that  it  swept  over  her  with  the  virulence 
of  plague.  In  September  1283,  when  Philip  the  Bold  of  France 
besieged  and  took  Gerona,  his  army  was  almost  destroyed  by 
pernicious  fever,  and  he  himself  succumbed  to  an  attack  at 
Perpignan.  In  this  epidemic,  according  to  Dormese,  great 
importance  was  attached  to  "  some  flies  which  caused  death 
by  their  bites,"  Of  its  ravages  in  the  Peninsula  no  better 
picture  has  been  given  us  than  that  of  Johnson  in  1771,  "the 
attack  of  Carthagena  is  yet  remembered,  where  the  Spaniards 
from  the  ramparts  saw  their  invaders  destroyed  by  hostility  of 
the  elements  ;  poisoned  by  the  air  and  crippled  by  the  dews  ; 
where  every  hour  swept  away  battalions ;  and  in  the  three 
days  that  passed  between  the  descent  and  the  embarkation 
half  an  army  perished."  From  historical  data,  it  is  clear  that 
the  greater  number  of  Spanish  authors  up  to  the  eighteenth 
and  first  half  of  the  nineteenth  century  in  many  cases  con- 
founded malaria  with  the  whole  group  of  infectious  diseases. 
In  these  times  one  Spanish  clinician,  Ludovic  Mercado, 
physician  to  Philip  II  and  Philip  III,  stands  apart  from  the 
rest,  for  in  1608  he  differentiated  pernicious  intermittent  fevers 
of  tertian  type  in  the  midst  of  the  pathological  chaos  around 
him.  In  1783  Masdevall  described  the  lamentable  effects  of 
malaria  in  Lerida  and  the  devastation  it  caused  among  the 
French  troops  massed  in  Cdceres.     He  pointed  out  the  relation 

399 


400  MALARIA   IN   SPAIN  [Sect. 

between  fever  and  the  pools  left  by  rivers  and  after  rains,  and 
remarked  that  the  greater  number  of  cases  were  always  found 
amongst  those  who  worked  in  the  sun  and  who  slept  at 
night  in  the  open  air.  He  completes  those  accurate  observa- 
tions by  recommending  the  use  of  Peruvian  bark  for  the  cure 
of  the  disease. 

In  the  first  years  of  the  nineteenth  century  (1800- 1805) 
several  papers  appeared  on  the  value  of  quinine  in  epidemics 
of  yellow  fever,  and  Nelson  in  one  of  his  last  letters  to  Lady 
Hamilton,  writes  of  "  the  dreadful  effects  of  yellow  fever  at 
Gibraltar,  and  in  many  other  parts  of  Spain." 

Though  Stegomyia  fasciata,  the  carrier  of  yellow  fever, 
exists  in  the  cities  of  Southern  Spain,  from  a  study  of  the 
symptoms,  and  course  of  this  fever  and  the  therapeutics 
employed  by  these  authors,  it  is  clear  that  they  were  dealing 
with  severe  types  of  summer  autumn  fever  with  hepatic 
symptoms. 

In  1888,  discussions  began  in  Spain  as  to  the  validity  of 
Laveran's  great  discovery,  and  till  1896  the  best  paper  on 
the  parasite  was  that  of  Thin  and  Marshall,  who  accurately 
described  the  types  of  fever  met  with  in  Southern  Spain. 
But  the  hypotheses  of  Laveran  and  Manson,  at  that  date 
passing  from  theory  to  fact  in  the  researches  of  Major  Ross, 
received  no  support  from  these  investigators  ;  for  their  con- 
clusions are  thus  presented  in  a  well-known  text-book  (1899): 
"  The  observations  of  Thin  and  Marshall  go  to  show  that  in 
the  province  of  Huelva  at  all  events  telluric  conditions  are 
the  permanent  factor  in  infection,  that  the  plasmodium  is  not 
usually  conveyed  by  water,  and  that  there  is  no  evidence  of 
the  mosquito  being  an  intermediary  host."  After  the  publica- 
tion of  Professor  Ross's  early  papers,  in  the  summer  of  1899 
we  began  to  investigate  malaria  in  the  same  province,  over 
an  area  of  60  miles,  extending  from  the  Rio  Tinto  mines  in 
the  foot  hills  of  the  Sierra  Morena  to  the  coasts  around  the 
town  of  Huelva.     In  the  hills  it  would  be  difficult  to  find  a 


48]  WORK   AT   HUELVA  401 

more  arid  district,  where  water  appeared  to  be  completely 
wanting-,  for  the  vegetation  within  a  three-mile  radius  had 
been  destroyed  by  the  fumes  of  sulphur  smoke.  It  lies  320 
metres  above  the  sea- level,  and  the  soil  is  chiefly  ironstone. 
Hardly  any  rain  falls  from  May  to  October  (fever  season), 
with  the  exception  of  rare  thunder-storms. 

The  aspect  of  the  country  is  that  of  undulating  hills  covered 
with  low  brush-wood  beyond  the  smoke  area.  The  valleys  in 
winter  are  often  filled  with  roaring  torrents.  In  summer  these 
streams  dry  up,  leaving  pools,  varying  in  size  from  about  3  ft. 
in  diameter  to  the  size  of  a  plate  or  saucer.  The  district  is 
dotted  over  with  small  villages  which  are  situated  on  the  slopes 
of  the  hills.  The  whole  area  was  more  or  less  malarious,  but 
certain  villages  were  notoriously  unhealthy,  and  it  was  a  curious 
fact  that  the  lowest  lying  village  was  the  healthiest,  though 
the  moving  of  earth  for  mining  operations  went  on  at  its  very 
doors.  Yet  half  a  mile  off,  where  most  of  the  British  employees 
lived,  fever  was  frequent.  In  September  1899,  we  showed  that, 
so  far  from  mosquitos  being  scarce  owing  to  the  presence  of 
sulphur  smoke,  they  abounded  in  the  district ;  and  in  the 
paludic  villages  Anopheles  maculipennis  was  often  the  only 
mosquito  to  be  found  in  the  houses.  In  the  Province  of 
Huelva  we  differentiated  the  following  varieties  of  mosquitos  : 
Anopheles  maculipennis^  Anopheles  superpictus  Grassi,  Myzotnyia 
superpictus  Blanchard,  Stegomyia  fasciata,  Culex  phytophagus, 
Culexpipiens,  Ctdex penicillaris  {Grathamia penicillaris  Rondani), 
Culex  spathipalpis  {Theobaldia  spathipalpis). 

In  south  Spain  A.  maculipennis  is  the  chief  carrier  of  malaria. 
A.  superpictus  is  not  often  met  with ;  we  have  only  found  it 
in  three  or  four  districts. 

We  have  always  found  that  the  abundance  oi  Anopheles  m 
any  district  is  in  relation  to  the  extent  of  malaria. 

Since  then,  repeated  observations  in  many  places  in  the 
South  of  Spain  have  always  shown  us  the  same  conditions  in 
fever  districts.     Whether  the    town    is   in  the  hills  or  on  the 

2  C 


402  MALARIA   IN   SPAIN  [Sect. 

plains,  the  dried  -  up  water-course  is  always  there,  the  pools 
sometimes  covered  with  algae.  In  the  hills  the  water  is  often 
running  slowly.  In  the  Sierra  we  have  found  Anopheles  larvae 
in  rocky  pools  devoid  of  vegetation,  but  as  a  rule  they  contain 
algae,  at  the  edges  of  which  the  larvae  swarm.  The  difficulty 
of  seeing  the  larvae  of  Anopheles  compared  with  those  of  Culex 
is  of  course  well  known  ;  and  in  some  cases  a  careful  examina- 
tion is  needed  before  concluding  that  there  are  none  in  the  pool. 
In  the  hills,  if  a  muddy  pool  and  a  clear  one  existed  side  by 
side,  we  constantly  noted  the  preference  of  Anopheles  for  the 
limpid  water.  As  a  general  rule  we  have  not  found  larvae  in 
artificial  collections  of  water  —  only  very  occasionally  in  old 
barrels  and  iron  tanks  on  a  railway  line.  In  mining  districts 
here,  dams  are  often  believed  to  be  a  source  of  malaria.  We 
have  not  yet  found  larvae  in  such  collections  of  water,  but 
have  often  demonstrated  them  in  the  ravines  within  50  metres 
of  the  dam. 

The  adult  insects  in  winter  and  spring  hibernate  here  in 
stables,  hen-houses  and  pig-styes,  where  they  can  always  be 
found  until  the  end  of  May  or  the  beginning  of  June.  After 
that  time  they  are  also  found  in  the  houses.  The  course  of  the 
epidemic  season  of  the  malaria  in  Spain  confirms,  as  elsewhere, 
the  strict  relation  there  is  between  the  human  infection  of  the 
previous  year  (winter  relapses,  cahectics,  children)  and  the 
infection  of  the  mosquito  in  June  and  July,  the  beginning  of 
the  fever  season.  Our  dissections  showed  that  the  percentage 
of  the  infected  mosquitos  in  June  was  only  7%,  while  towards 
the  end  of  July  and  in  August  it  rose  to  18%. 

Of  Anopheles  captured  in  stables,  etc.,  none  were  found 
infected.  We  frequently  found  red  larvae  of  Hydrachnides 
fixed  on  the  insects,  and  sections  of  some  Anopheles  which  died 
rapidly  in  captivity  were  examined  by  Laveran  and  were  found 
to  contain  a  fungus  in  the  wall  of  the  stomach  and  in  the 
coloemic  cavity,  which  possibly  may  be  pathogenic  for  the  insect. 
For  infection  experiments,  we  fed  A.  viaculipemiis  on  fever 


48]  OTHER   PARTS  403 

cases,  and  weak  hematine  gave  us  good  results  in  staining 
the  zygotes.  Sometimes  no  infection  of  the  insect  took  place, 
or  the  zygotes  failed  to  reach  maturity.  We  felt  that  such 
variations  were  probably  due  to  the  diet  of  the  mosquito,  and 
a  note  by  Sehoo  of  Holland  confirmed  this ;  for  he  pointed 
out  the  importance  of  avoiding  acid  fruit  in  the  food  of  insects 
under  infection  experiments,  and  when  we  fed  them  on  melons 
the  growth  of  the  zygotes  was  uninterrupted. 

The  role  then  of  Anopheles  in  Spain  admits  of  no  doubt  • 
and  the  mosquito  has  never  been  found  wanting  in  malarial 
districts  in  the  fever  season  when  searched  for  by  competent 
observers. 

These  investigations  were  confirmed  elsewhere  in  Spain 
by  Huertas  and  Mendoza  in  the  province  of  Caceres,  and  by 
Pittaluga  in  Catalonia  (Barcelona),  Valencia,  Madrid,  and  the 
Balearic  Isles,  where  he  found  A.  maculipennis,  A. psendopictus, 
A.  superpictus  and  A.  bifurcatus. 

In  1903  Pittaluga  collected  the  investigations  up  to  date 
on  malaria  in  Spain,  and  from  the  papers  of  different  writers 
in  that  volume  some  idea  was  obtained  of  the  extent  of  malaria 
in  modern  Spain.  His  map  gives  a  good  idea  of  its  distribution. 
Though  exact  data  are  difficult  to  obtain,  it  is  quite  apparent 
that  the  disease  still  reigns  with  great  severity  in  the  Peninsula. 
In  1900  there  were  4,703  deaths  from  malaria  in  Spain  in  a 
population  of  18,300,000,  which  is  a  malarial  mortality  of  0*25 
per  milk.  In  relation  to  the  general  mortality  of  536,716  (29-3 
per  mille),  this  represents  1/114  of  the  general  mortality,  or 
9  per  1,000  of  the  cases  of  death.  In  1898  and  1899,  when 
the  troops  came  back  from  Cuba,  the  malarial  mortality  rose 
immediately,  and  probably  gave  in  each  of  these  years  a 
mortality  of  not  less  than  8,000  per  annum.  The  following 
figures  from  a  railway  company  give  a  further  idea  of  the 
ravages  of  malaria  in  Spain  to-day.  In  1902  12,746  employees 
were  treated  medically  or  surgically,  and  of  these  1,904  were 
malaria  patients.    Five  deaths  were  directly  attributable  to  fever 


404  MALARIA   IN   SPAIN  [Sect. 

and  the  company  lost  14,275  days'  work  in  consequence  of  the 
disease. 

On  certain  divisions  of  the  line  this  company  keeps  a  double 
personnel  to  alternate  every  fifteen  days,  and  the  employees 
themselves  call  one  notoriously  unhealthy  area  "  Little  Cuba," 
where  their  doctors  admit  that  the  mortality  is  equal  to  that 
of  tropical  countries. 

After  these  researches  some  stimulus  was  given  to  prophy- 
laxis, but,  so  far,  in  Spain  it  has  only  been  undertaken  by  a 
few  companies  and  private  individuals.  In  a  country  where 
typhus  last  year  raged  in  her  capital,  and  the  isolation  hospital 
is  unknown  in  her  provinces,  sanitation  is  only  in  its  infancy^ 
In  the  city  of  Badajoz  in  1899,  in  one  street  500  people  were 
attacked  by  malaria,  and  the  supply  of  quinine  ran  short  in 
the  town.  Yet  no  municipality  has  yet  organised  a  scheme 
of  prophylaxis. 

Through  the  kindness  of  Dr  Varela  we  are  enabled  to 
submit  the  following  figures  from  the  Madrid,  Zaragoza,  and 
Alicante  Railway,  where  protection  of  the  railway  servants' 
houses  by  wire-gauze,  and  the  administration  of  quinine,  are 
the  methods  employed,  and  have  given  a  gradual  but  steady 
diminution  in  the  cases  of  fever  : — 

1901-1902  no  protection  631  cases 

1903-1904  with  protection  306      „ 

1905  „  „  190      „ 

In  Rio  Tinto,  supported  by  a  company  which  recognises 
the  importance  of  the  health  of  their  staff,  we  initiated  measures 
of  prophylaxis,  on  a  small  scale,  which  have  been  continued 
under  the  direction  of  Dr  Russell  Ross,  the  chief  medical  officer, 
with  eminently  satisfactory  results.  The  English  staff  of  this 
compan)',  with  their  wives  and  families,  number  about  170 
persons.  They  live  in  a  group  of  thirty  houses,  in  close 
proximity  to  the  ravines  where  Anopheles  pools  are  found. 
A  few  years  ago  in  the  malarial  season  each  house  had  its 
fever  patient,  and  the  place  was  notoriously  unhealthy.      The 


48]  RIO   TINTO  405 

pools  are  now  filled  up  or  drained  away ;  and,  where  it  is 
impossible  to  remove  the  water  completely,  narrow  channels 
are  made  by  which  a  rapid  flow  is  maintained,  and  stagnation 
prevented.  Simple  open  drains  have  been  laid  in  the  bed  of 
some  water-courses.  The  use  of  nets  is  recommended,  and 
some  families  have  their  houses  protected  by  wire-gauze.  The 
effect  on  the  number  of  mosquitos  has  been  marked,  for  now 
they  are  hardly  ever  seen.  Hen-roosts  and  places  harbouring 
domestic  animals  are  smoked  out  once  a  week  by  a  mixture 
producing  sulphurous  acid  gas.  The  diminution  in  the  cases 
of  malaria  may  be  seen  by  reference  to  the  following  table 
which  we  owe  to  the  kindness  of  Dr  Ross : — 

Cases  of  acute 
malaria 

25 

2 

O 

o 
I 

The  attack  on  the  Anopheles  pools  has  recently  been 
extended  to  the  ravines  round  the  workmen's  villages,  where 
gangs  of  men  under  supervision  drain  away  and  fill  in  the  pools. 

The  improvement  in  the  health  of  the  people  has  been 
most  marked.  In  former  years  departments  with  2,0(X)  men 
at  times  had  hundreds  incapacitated  by  fever,  and  difficulty 
was  sometimes  found  in  maintaining  the  service.  Now,  though 
some  cases  still  occur,  fever  never  rages  to  the  extent  it 
did  formerly.  Villages  which  were  recognised  as  hot-beds  of 
malaria,  and  consequently  avoided  by  the  workmen,  have  been 
rendered  comparatively  healthy  again.  The  cost  of  these 
measures  in  Rio  Tinto  and  its  environs  is  less  than  £\Q0 
per  annum  ;  but  costs  are  lessened  by  assistance  given  by  the 
various  departments  of  the  mine.  Ten  years  ago  there  was 
a  yearly  despatch  of  1,225  oz.  of  quinine;  it  is  now  reduced 
to  900  oz.,  though  there  is  an  increase  of  50%  in  the  number 
of  workmen. 


Cases  of  illness 

1896     . 

no  prophylaxis 

89 

1906-07 

61 

1907-08 
1908-09 

prophylaxis 

64 

78 

1909-Ioj 

80 

By  Professor  ANGELO  CELLI 

Director  of  the  Institute  of  Hygiene,  University  of  Rome 

49.  The  CampaigTi  against  Malaria  in  Italy.^— In  my  report 
to  the  International  Congress,  held  at  Brussels,^  I  described  how 
a  Society  for  the  study  of  malaria  in  Italy  had  arisen,  and 
stated  that  it  had  initiated  its  work  for  the  purposes  of  know- 
ing better  and  vigorously  combating  this  grave  scourge  of  our 
country. 

I  have  much  pleasure  now  in  noting  summarily  the  results 
obtained  from  1903  till  to-day. 

Since  Ross's  discovery  was  confirmed  and  consolidated  by 
the  work  of  some  of  our  members,  and  later  by  many  other 
workers,  we  have  continued  to  work  in  the  scientific  and 
practical  fields. 

In  the  scientific  field  we  have  made  researches  on  the  etiology, 
physio-pathology,  epidemiology  and  prophylaxis  of  malaria. 

In  the  practical  field  we  have  introduced  new  and  improved 
prophylactic  measures  into  medical  use,  legislation  and  the 
habits  of  the  people. 

In  order  to  keep  within  the  narrow  limits  assigned  to  me,  I 
can  note  only  the  following  facts  : — 

^  Owing  to  pressure  of  work,  Professor  Celli  has  asked  me  to  take  for  his  contribution 
to  this  book  his  article  in  the  Journal  of  Tropical  Medicine  for  1st  April  1908  (trans- 
lated by  Dr  John  J.  Eyre),  with  special  additions.  The  editor  of  the  Journal  has 
kindly  permitted  this. — R.  Ross. 

2  Septime  Section.  "  Hygiene  Coloniale,  Deuxieme  Question  :  Prophylaxie  de  la 
Malaria,"  vol.  viii. ,  Bruxelles,  1903,  and  Giornale  della  R.  Soc.  ital.  d'/giene,  Milan, 
1903. 

406 


Sect.  49] 


QUININE   AND    MORTALITY   TABLE 


407 


FIG.  I. — MORTALITY  FROM  MALARIA  AND  THE  CONSUMPTION  OF  QUININE 

IN   ITALY. 

I  Annual  number  of  deaths  from  malaria  from  1887  (upper  part). 

^  Kilograms  of  quinine  imported  by  private  measures  from  1 89 1  onwards. 

^  Kilograms  of  State  quinine  sold  yearly  from  1902  (lower  part). 


4o8        THE   CAMPAIGN  AGAINST   MALARIA  IN  ITALY    [Sect. 

I.— The  Principles  of  Epidemiology 

By  our  researches  it  has  been  demonstrated  and  confirmed 
in  different  ways  that : — 

(i)  Man  is  the  only  source  at  present  known  of  malarial 
infection. 

(2)  Not  only  infants,  but  also  children  and  adults,  are  the 
bearers  of  the  infective  germs. 

(3)  The  recurrences,  sometimes  obstinate,  in  spite  of  every 
kind  of  treatment,  are  the  most  marked  characteristic  of  every 
form  of  malarial  fever.  They  maintain  the  contagion  between 
the  healthy  and  the  diseased  from  one  epidemic  year  to  the 
next,  and  are  one  of  the  main  causes  which  regulate  the  local 
and  annual  variations  of  the  malarial  epidemics. 

(4)  As  the  indication  of  an  epidemy,  it  is  necessary  to  take 
into  consideration : — 

(a)  The  infantile  malarial  morbidity  and  the  relative  splenic 
enlargement:  this  splenic  index,  as  it  is  named  by 
Christophers  and  Stephens,  may  be  easily  ascer- 
tained, but  is  neither  exact  nor  exclusive  ;  moreover, 
it  does  not  suffice,  when  alone,  to  indicate  the 
intensity  of  an  epidemic, 

(^)  The  morbidity  in  the  whole  population  or  in  some 
classes  of  it  (country  people,  miners,  soldiers,  railway 
employees). 

(c)  The  recurrent  cases  which  are  more  or  less  obstinate. 

(d)  The  numerical  relation  between  the  aestivo-autumnal  and 

the  mild  tertian  fever  cases. 

(e)  The  more  or  less  severe  clinical  features  and  complica- 

tions (haemoglobinuria). 
(/)  The  manifestation  of  domestic  epidemics  or  of  sporadic 

cases. 
(£■)  The  total  or  absolute  mortality  related  to  the  whole 

population  (relative  mortality),  or  the  one  related  to 


49]  GENERAL   PRINCIPLES  409 

the  number  of  the  infected  individuals  (pernicious- 
ness  or  lethality  from  malaria), 
(/z)  Demographic  indications,  especially  the  excess  of  deaths 
over    births    and   the    following    depopulation    and 
desolation   which  are  but   too   sad   a  characteristic 
of  malarious  lands. 
When  we  take  into  account  all  these  indications,  we  may 
every  year  not  only  exactly  establish  the  course  of  epidemics 
in  our  districts,  but  also  precisely  compare  our   observations 
with  the  international  ones. 

An  historical  description  of  epidemics  in  these  last  years,  by 
making  use  of  the  above  -  mentioned  indications,  would  be 
possible  only  for  small,  well  -  circumscribed  and  thoroughly 
studied  areas. 

Therefore  we  must  generally  content  ourselves  with  the 
mortality  index,  and,  so  far  as  possible,  with  the  morbidity 
index  too. 

(5)  The  severe  tertian,  the  mild  tertian,  and  the  quartan 
have  each  a  special  type  of  epidemy ;  that  is  to  say,  the  first  is 
aestivo-autumnal  proper,  the  second  is  the  only  one  which 
presents  itself  in  the  spring,  the  third  is  principally  autumnal. 

(6)  The  Anopheles  are  never  wanting  where  the  fevers  exist, 
but  their  quantity  is  not  always  in  direct  proportion  to  the 
intensity  of  the  epidemy  ;  in  fact,  it  is  frequently  in  inverse 
proportion.  On  the  other  hand,  there  may  be  plasmodia  and 
Anopheles  without  malaria  developing  itself,  even  when  malarial 
patients  arrive  there  from  other  places,  or  some  autochthonous 
or  sporadic  case  of  fever  manifests  itself  there.  Plasmodia  and 
Anopheles  may  therefore  persist,  and,  notwithstanding  this,  the 
malaria  may  become  attenuated  and  disappear. 

(7)  The  number  of  Anopheles  infected  is  always  small,  even 
in  the  places  and  months  most  affected  by  the  fevers.  The 
hereditary  transmission  of  the  infection  from  mosquito  to 
mosquito  has  not  been  demonstrated  up  to  now. 

(8)  Various  annual  epidemic  types  exist,  namely : — 


4IO        THE   CAMPAIGN   AGAINST  MALARIA  IN   ITALY    [Sect. 

{a)  The  South  of  Italy  type,   with  great  predominance  of 
the  aestivo-autumnal  parasites,  with  virulence  gener- 
ally exalted. 
{b)  The  North  of  Italy  type,  with  more  or  less  predominance 
of  the  parasites  of  the  mild  tertian  and  the  initiation 
of  this  in  the  spring. 
(c)  The    North   of    Europe   type,   with   the   absolute   pre- 
dominance of  the   mild  tertian  and  the  precocious 
development  of  the  epidemy  in  the  spring. 
In  Hungary,  Greece  and  Russia  epidemic  types  like  those 
observed  in  Italy  are  met  with, 

(9)  The  mortality  from  malaria  in  the  whole  of  Italy  from 
1887  onwards  {cf.  fig.  i,  upper  part)  has  been  subject  to  regular 
periodic  oscillations,  with  a  maximum  every  five  or  six  years. 
This  periodic  course  is  most  marked  in  the  most  malarious 
regions — namely,  from  Latium  downwards,  and  in  the  islands 
{cf.  fig.  2),  while  in  the  rest  of  Central  and  North  Italy  the 
progressive  descent  without  notable  variations  is  manifest. 

The  morbidity  also  from  malaria  in  the  Rome  hospitals  is 
subject  to  periodic  oscillations  which  in  the  last  fifteen  years 
have  reached  their  maximum  every  five  years. 

No  relation  has  been  as  yet  established  between  the  meteoro- 
logical conditions  and  the  annual  and  periodic  epidemic  oscilla- 
tions, which  would  seem  to  be  due  more  to  general  biological 
properties  inherent  in  the  specific  parasites  themselves  than  to 
climatic  reasons. 

(10)  In  the  study  of  the  malarial  epidemics,  besides  infected 
men  and  Anopheles,  it  is  necessary  to  take  into  consideration 
also  other  predisposing  or  immunising  causes  of  biological  or 
organic  {x),  physical  or  local  {y),  economic  or  social  {s)  origin. 
Although  they  are  unknown  in  their  intimate  mechanism  of 
action,  nevertheless  they  have  undoubted  influence  both  on  man 
and  on  Anopheles,  and  hence  they  may  stimulate  or  impede  the 
development  of  a  malarial  epidemy.  Therefore,  for  the  primary, 
very  simple  equation:    Malarial   man-\- Anopheles  =  epidemy  of 


49]  TABLE   OF    RESULTS  4" 

malaria,  we  must  substitute  this  other  :  Malarial  man  ■'r  Anopheles 
+  x,y,  5  =  epidemy  of  malaria.^ 

(ii)  The  above-mentioned  facts  show  that  the  problems  of 


NUMBER 
OF  DEATHS 

887 

BST 

89 

90 

91 

92 

93 

94 

95 

96 

97 

98 

99 

900 

01  02  03 

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05 

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FIG     -^  —MORTALITY   FROM   MALARIA   IN   THE    REGIONS   OF   ITALY   BEFORE 
AND   AFTER   THE   STATE   QUININE. 

Latium  and  South  Italy. 

-    -    -   Sicily  and  Sardinia.  ,   t    i  \ 

Central  Italy  (excluding  Latium  and  North  Italy). 

the  epidemiology  and  prophylaxis  of  malaria  cannot  be  con- 
sidered from  a  narrow  point  of  view. 

II._The  Measures  for  Combating  Malarial  Epidemics 
Our  first  attempts  were  directed  to  the  destructmi  of  the 
mosquitos  by  physical    and    chemical    means.     The   laboratory 
1  Compare  section  28. — R.  Ross. 


412        THE   CAMPAIGN   AGAINST   MALARIA  IN   ITALY    [Sect. 

experiments  were  encouraging.  Later  attempts,  with  great 
perseverance,  were  carried  out  by  Galli-Valerio  and  by  J. 
Rochaz  de  Jong,  by  biological  means  (animals  and  plants  which 
kill  mosquitos  or  impede  their  development).  On  carrying  this 
into  practice  on  a  large  scale  one  meets  with  many  difficulties 
owing  to  which,  at  least  among  us,  with  so  many  extensive 
marshes  and  so  much  intensive  culture,  one  cannot  succeed, 
save  in  exceptional  cases  and  by  long  and  assiduous  work,  in 
destroying  malaria  by  means  of  the  destruction  of  mosquitos. 

Nevertheless,  to  the  old  and  reliable  methods  of  the  campaign 
against  malaria,  namely,  draining  and  agrarian  sanitation^  our 
efforts  were  directed. 

The  hygienic  effects  of  the  sanitation  by  drainage  already 
carried  out  were  studied.  The  result  was  that  on  large 
extensions  of  land  the  best  drainage  sanitation  very  frequently 
failed  to  drain  off  all  the  water  or  to  give  it  sufficient  velocity  to 
impede  the  aquatic  life  of  Anopheles.  Frequently,  also,  the 
deficiency  of  the  neglected  state  of  the  complementary  drains 
and  of  the  discharging  canals  helped  to  maintain  the  anophelism. 

Consequently,  very  often  the  drainage  improvement  is  not 
synonymous  with  sanitation,  to  which  one  will  arrive  in  time, 
when  the  agrarian  sanitation  supervenes,  which,  therefore,  must 
be  the  necessary  complement  of  the  drainage  improvement. 

Both,  however,  as  we  shall  see,  can,  and  should,  be  facilitated 
and  shortened  —  with  incalculable  saving  in  health  and  time 
— by  means  of  the  medical,  mixed,  or  at  least  the  quinine 
prophylaxis. 

In  its  turn  the  agrarian  sanitation  helps  to  improve  the 
conditions  of  life  of  the  worker  by  better  housing,  alimentation, 
work  and  clothing.  These  coefficients,  together  with  improved 
medical  assistance  and  the  consumption  of  quinine,  have  led 
after  a  long  time,  and  now  lead  more  quickly,  to  the  sanitation 
of  a  territory,  even  where  paludism,  with  the  relative  anophelism, 
still  exists,  and  even  can  usefully  exists  inasmuch  as  it  helps  to 
render,  by  the  utilisation  of  the  waters,  the  agriculture  more 
prosperous. 


49]  MEASURES   COMPARED  413 

Keeping  away  infected  mosquitos  from  the  person  and  frotn 
the  house  is  another  mode  of  protecting  oneself  from  malaria, 
which  is  directly  derived  from  the  new  theory. 

However,  if  man  on  whom  this  scourge  weighs  should  wish 
to  free  himself  from  it  only  by  the  mode  which  is  directly 
derived  from  the  theory  of  the  Anopheles,  that  is,  by  the  destruc- 
tion, or  at  least  by  the  keeping  away  of  these  insects,  who 
knows  how  long  he  would  have  to  wait  ? 

We  refer  to  the  difficulties  met  with  by  us  in  our  campaign 
in  endeavouring  to  destroy  the  mosquitos. 

A  quicker  and,  within  certain  limits,  a  more  easy  method  is 
to  prevent  them  biting  one  by  keeping  them  away.  But  only  the 
minor  part  of  the  population,  namely,  the  richer  and,  therefore,  the 
least  attacked,  can  enjoy  this  benefit. 

In  fact,  in  order  to  prevent  the  bites  of  mosquitos  one 
requires,  above  diW,  proper  clothing,  which  frequently  is  wanting, 
and  owing  to  the  great  heat  cannot  be  supported  ;  thus,  also, 
the  gloves  and  masks  for  protecting  the  uncovered  parts  of  the 
body  are  very  inconvenient,  and  prevent  one  working. 

Odours,  ointments,  and  washes  containing  culicidal  sub- 
stances, which,  according  to  our  researches  and  those  of  others, 
are  many,  have  a  very  restricted  action  in  closed  spaces,  and 
little  or  no  action  in  the  open  air. 

On  the  other  hand,  he  who  can  live  in  some  kind  of  habita- 
tion, with  all  the  openings  protected  with  wire  -  netting  to 
prevent  the  entrance  of  mosquitos,  can  thus,  as  a  rule,  preserve 
himself  from  malaria. 

This  method,  which  was  first  adopted  by  us  in  1899,  by  our 
advice  is  coming  more  and  more  into  use  in  the  houses  along 
the  railways,  as  shown  from  the  subjoined  table. 

This  mechanical  prophylaxis  has  been  adopted  in  the 
Custom-house  officers'  barracks. 

It,  however,  is  not  equally  practicable  for  soldiers. 

Unfortunately,  owing  to  the  first  cost  and  that  of  repair,  it 


414        THE   CAMPAIGN   AGAINST   MALARIA  IN   ITALY    [Sect. 

is  an  expensive  prophylaxis  ;  besides,  it  presupposes  a  special 
hygienic  education  in  those  who  inhabit  the  protected  houses, 
and  that  they  should  retire  there  during  the  most  dangerous 
hours  of  the  day,  things  which  are  very  far  removed  from  the 
mode  of  life  to  which  our  peasants  are  accustomed. 

TABLE   I 

Mechanical  Prophylaxis  along  the  Adriatic  Railways 


Percentage  attacked 

Percentage  of 

WITH  FEVER. 

CONTROLS  attacked. 

Year. 

Persons 
protected. 

Recurrent. 

Primary. 

Min. 

Max. 

1899 

24 

20 

20 

96 

_ 

1900 

27 

5-5 

7-5 

n 

92 

I901 

5,165 

3-3 

20-2 

20 

96 

1902 

5,851 

lOI 

2" 

12 

81 

1903 

8,230 

22-5 

4-6 

10 

32 

1904 

12,378 

87 

2-0 

10 

27 

Fortunately,  much  easier  and  quicker  results  can  be  obtained, 
when  one  wishes  it,  by  the  proper  administration  of  quinine. 

It  is  very  well  known  that  quinine  is  a  truly  sovereign 
remedy,  both  for  disinfecting  the  blood  of  malarial  patients  and 
for  provoking  an  artificial  medicamental  immunity.  But  this 
very  powerful  weapon  with  a  double  edge  has  not  been  well 
managed  by  others;  whereas  in  our  hands  it  has  constantly 
increased  in  value,  not  only  for  the  curative  treatment,  but  also 
for  the  preventive  treatment  of  malaria. 

There  is  no  doubt  that  this  remedy  acts  in  inverse  pro- 
portion to  the  degree  of  development  of  the  malarial  parasites 
in  the  blood-stream  ;  that  is  to  say,  it  acts  best  against  the 
sporozoites  directly  they  are  inoculated,  and  least  against  the 
forms  destined  to  maintain  the  recurrent  fevers,  and  little  or 
not  at  all  against  the  sexual  forms  destined  to  propagate  the 
species.     We  have  thus  proved  over  and  over  again  that  some 


49]  PREVENTION    BY   TREATMENT  415 

fevers  are  pertinacious  in  recurring  in  spite  of  the  abundant 
and  protracted  use  of  quinine,  either  alone  or  associated  with 
the  so-called  reconstituents  (iron  and  arsenic).  In  fact,  these 
latter  drugs,  under  whatever  form  and  in  whatsoever  way 
administered,  have  no  value  as  direct  anti-malarial  remedies. 

It  follows  from  this  that  even  the  best  treatments  in  the  pre- 
epidemic  period  do  not  succeed  in  preventing,  as  Koch  thought 
they  would,  the  development  of  malaria  in  the  following  summer. 
Therefore,  by  the  quinine  treatment  alone  to  extirpate  malaria 
from  an  extensive  locality  is  much  more  difficult  than  one 
would  a  priori  imagine.  In  any  case,  it  must  be  the  work  of 
long  duration,  that  is  to  say,  treating  in  every  period  of  the 
year,  day  by  day,  energetically  and  assiduously,  every  case  of 
malarial  fever. 

Quinine,  however,  is  the  best  remedy  for  the  radical  treatment 
of  malaria,  even  latent  and  recurrent.  The  essential  thing  is  to 
continue  the  treatment  for  a  long  time  with  great  patience  and 
perseverance ;  and  the  secret  of  success  is  to  administer  the 
quinine  in  the  most  agreeable  and  therefore  also  the  most  tolerable 
form.  Besides,  it  is  better,  when  possible,  to  call  in  the  aid  of 
other  means  pre-eminently  beneficial,  such  as  alimentation, 
habitation,  clothing  and  moderate  work. 

Since,  therefore,  the  latent  and  recurrent  infections  cannot 
be  prevented,  much  less  eradicated,  //  is  necessary  to  do  every- 
thing to  prevent  completely  the  malarial  infection  itself. 

The  quickest  and  best  results  regarding  the  preventive  treat- 
ment are  obtained  by  quinine  administered  for  this  purpose. 

To  establish  firmly  the  scientific  and  practical  basis  of  this 
preventive  treatment  of  malaria  has  been,  since  1900,  one  of  the 
principal  tasks  we  have  undertaken. 

Thus,  by  degrees,  with  the  assistance  and  control  of  able 
collaborators,  we  have  come  to  the  following  conclusions : — 

{a)  That  quinine,  provided  it  be  administered  daily,  is  in 
average  and  even  therapeutic  doses  better  tolerated,  and  for  a 
longer  time  than  a  priori  one  could  have  believed  ;  that  is  to 


4i6        THE   CAMPAIGN   AGAINST  MALARIA  IN    ITALY    [Sect. 

say,  after  the  first  two  or  three  days  it  no  longer  produces  the 
least  singing  in  the  ears,  and  is  not  only  completely  innocuous, 
but  also  acts  as  an  aid  to  nutrition  and  as  a  tonic  to  the 
digestive  apparatus  and  muscles,  thereby  increasing  the  appetite 
and  the  power  of  work. 

(b)  Quinine  taken  daily  is  always  present  in  the  blood,  and 
thus  prevents  instead  of  producing  the  phenomena  of  quininism. 
Further,  there  is  not,  perhaps,  another  example  of  a  remedy  so 
perfect,  nor  one  which  so  rapidly  establishes  itself,  and  can  be 
prolonged  for  a  long  time  (up  to  five  or  six  months),  and  yet 
can  be  interrupted  when  desirable  without  any  disturbance,  and 
without,  although  the  organism  is  habituated  to  the  small  and 
average  doses,  diminishing  the  curative  efficacy  of  the  large 
doses  when  they  are  necessary. 

{c)  But  if  quinine  be  given  at  intervals  longer  than  three 
days  the  phenomena  of  quininism  present  themselves  every 
time ;  in  consequence  the  method  of  intermittent  administration, 
namely,  every  four  days  (Ziemann),  every  five  (Plehn),  every 
seven  to  ten  (Koch),  although  recommended  by  these  able 
workers,  is  not  preferable  to  our  continuous  and  daily  method. 

The  administration  at  intervals  of  every  two  or,  at  the  utmost, 
of  every  three  days  (Sergent)  may  be  in  some  cases  employed. 

Longer  intervals  are  not  to  be  recommended,  owing  to  the 
disappearing  of  quinine  from  the  blood  three  days  after  the 
administration. 

{d)  Intolerance  to  the  salts  of  quinine  insoluble  in  water,  if 
they  be  administered  in  average  doses  daily,  is  met  with  in 
very  few  persons,  and  up  till  now  we  have  never  observed  the 
haemoglobinuria  which  the  intermittent  method  and  the  relative 
large  doses  have  not  succeeded  in  preventing. 

{e)  Intolerance  very  exceptionally  manifests  itself  if  a  salt 
insoluble  in  water,  such  as  tannate  of  quinine,  be  given.  This 
salt  is  slowly  absorbed,  especially  in  the  intestine,  by  the  work 
of  the  bile  and  of  the  pancreatic  juice,  and  it  is  perhaps  for  this 
reason  that  it  has  the  value  of  being  generally  atoxic,  even   in 


49]  QUININE  417 

persons  who  have  a  special  idiosyncrasy  for  haemoglobinuria 
towards  the  salts  soluble  in  water.  By  reason  of  this  ordinary 
atoxicity,  as  well  as  the  absence  of  bitter  taste,  it  is  specially 
indicated  for  young  children,  and  for  those  adults  who  show 
intolerance  for  the  other  salts  or  suffer  from  malaria  com- 
plicated by  gastro-intestinal  disturbances. 

(/)  According  to  Mariani  and  Giemsa  also,  quinine  proper 
that  is,  in  the  basic  state,  is  absorbed,  and  acts  very  well.  Con- 
sequently, the  solubility  or  not  in  water  of  a  preparation  of 
quinine,  or  its  administration  with  the  stomach  full  or  empty,  do 
not  in  the  least  deserve  that  importance  which  has  been  and  is 
attributed  to  them. 

(^)  An  essential  coefficient  of  true  tolerance  is  to  administer 
it  in  an  agreeable  form  ^  hence  the  forms  of  comfits  or  chocolates 
which  we  have  persistently  proposed  for  the  various  salts  of 
quinine. 

(Ji)  He  who  takes  quinine  every  day,  and  therefore  has 
always  a  supply  of  quinine  in  the  blood-stream,  can  undergo 
with  impunity  inoculations  of  blood  full  of  malarial  parasites,  and 
can  expose  himself  with  little  or  no  danger  to  the  bites  of 
infected  mosquitos.^ 

(f)  Arsenic  and  iron  do  not  display  any  protective  anti- 
malarial action,  either  experimentally  or  chemically  demonstrable. 

These  are  the  scientific  and  practical  facts  on  which  we 
have  based  the  method  of  preventing  new  infections,  and  of 
reducing  the  recurrences  by  means  of  the  daily  administration 
of  quinine  in  average  doses,  namely : — 40  centigrams  of  the 
bisulphate,  hydrochlorate  or  bihydrochlorate  of  quinine  for 
adults  and  young  persons ;  20  centigrams  of  the  same  salts,  or 
30  centigrams  of  tannate  of  quinine  for  children  ;  and  in  every 
case  administered  in  the  agreeable  form  of  comfits  or  of 
chocolates.  These,  especially,  owing  to  the  sugar  and  cocoa 
have  overcome  the  dread  and  prejudice  against  the  prophy- 
lactic use  of  quinine. 

^  See  end  of  section  16  and  section  65. — R,  Ross. 

2  D 


4i8        THE   CAMPAIGN   AGAINST   MALARIA  IN  ITALY    [Sect. 

In  districts  with  very  severe  malaria  the  above  doses  are 
increased  to  50  or  60  centigrams  for  adults  and  young  persons, 
and  one  can  or  must  substitute  the  bisulphates  for  the  bihydro- 
chlorate  of  quinine.  In  districts  with  mild  malaria  the  indicated 
preventive  treatment  of  children  may  be  given  on  alternate 
days. 

The  efficiency  of  our  method  is  demonstrated  by  the  follow- 
ing figures,  which  show  the  rapidly  increasing  number  of  persons 
who,  in  virtue  of  the  work  of  our  members  from  year  to  year, 
have  benefited  by  this  preventive  treatment. 


TABLE   II 
Quinine  Prophylaxis  in  Italy 


Year. 

Number  of 
persons 

treated  for 
I  to  5  months 
with  preven- 
tive quinine. 

Attacked  by  fevers. 

Locality. 

Persons  treated. 

Percentage  of 
control. 

Total. 

Percentage. 

Min. 

Max. 

1900 

1901 
1902 
1903 
1904 
1905 
1906 
1907 
1908 

116 

538 

3,055 

19,021 

52,690 

59,340 

110,804 

100,816 

102,572 

52 

30 

335 

932 

4,262 

3,458 
7,115 
4,192 
5,780 

IO-3 

5-5 
77 
5-6 
8-0 
5-8 
6-4 

4T 

57 

63 

20 
12 
38 

8 
9 
9 

60 
81 
90 
80 
82 
50 

Agro    Romano    and 
Pontine  Marshes. 

,,                 ,, 

,,                 ,, 

,,                 ,, 

Various  parts  of  Italy. 

,,                 ,, 
,,                 ,, 
,•                 ,, 

,,                 ,, 

In  its  turn  Table  III  demonstrates  that  in  the  Agro 
Romano,  which  has  been  the  birthplace  of  this  prophylaxis, 
owing  to  the  initiative  of  our  Society,  the  Red  Cross  Society 
and  the  rural  doctors  of  the  communes  of  Rome,  while  the 
number  of  immunised  continually  increased  from  1900  onwards, 
the  cases  of  primary  fevers  and  of  all  malarial  ailments  treated 
by  the   Red   Cross  diminished,     Further,   the  Rome  hospitals 


49] 


QUININE 


419 


admitted  a  much  smaller  number  of  cases  in  the  years  1902- 
1904,  barely  felt  the  usual  quinquennial  recrudescence  of  1905, 
and  admitted  a  minimum  number  of  cases  in  1906. 

TABLE   III 
Quinine  Prophylaxis  in  the  Agro  Romano 


1900. 

1 901.    1902. 

1903. 

1904. 

1905- 

1906. 

1907. 

1908. 

Prophylaxis   in   the    Agro 

79 

1,176 

3,8S3 

17.506 

29,693 

38,429 

42,726 

34.927 

33.808 

Romano 

Primary  infections  treated 

1,716 

1,263 

764 

320 

162 

250 

129 

166 

127 

by  the  Red  Cross  Society 

(17) 

(13) 

(7) 

(2) 

(1-34) 

(1-52) 

(0-7) 

(i'44) 

(1-62) 

Malarial    patients    treated 

3.751 

2,366 

2,581 

1.547 

1,406 

839 

576 

371 

437 

by  the  Red  Cross  Society 

(,V) 

(26) 

(20) 

(") 

(10) 

(51) 

(3-4) 

(3-2) 

(2-0) 

Malarial  patients  admitted 

6,t86 

4.725 

2,750 

2,461 

2,991 

3.991^ 

2.513 

2,486 

2.748 

into  the  Rome  hospitals 

1  Year  of  periodic  epidemic  recrudescence 
The  figures  in  parentheses  are  the  percentages. 

The  unanimous  agreement  of  both  the  doctors  and  patients 
during  these  last  years  have  convinced  us  more  and  more  that 
this  daily  quinitie  treatment  diminishes  notably  the  recurrence^ 
causes  the  perniciousness  to  disappear^  prevents  cachexia,  and  very 
frequently  the  primary  infections,  and  at  least  reitders  the  fevers 
milder  and  more  readily  curable  by  simply  increasing  the  quinine 
for  a  few  days  to  the  therapeutic  dose  and  then  returning  to  the 
prophylactic  dose. 

Hence  it  is  that  from  the  Agro  Romano,  where  we  made 
our  first  experiments,  the  daily  use  of  quinine,  which  is  as 
necessary  as  daily  bread  in  the  districts  and  months  of  malaria, 
has  to-day  extended  to  every  malarious  province  of  Italy,  and 
it  is  extending  more  and  more  among  the  rural  populations,  the 
State  employes  living  along  the  railways,  and  in  the  Army. 
Its  further  extension  to  those  who  need  it  is  a  question  of  time, 
that  is,  of  education  and  organisation.  Inasmuch  as,  in  order 
to  convince  oneself  of  its  value,  it  is  sufficient  to  try  it,  he 
who  has  done  so  proclaims  its  value  and  goes  on  using  it ;  and 
thus  by  entering  gradually  into  the  habits  of  the  country  people,  it 
acquires  a  wide  field  of  beneficial  action,  especially  among  the 


420        THE  CAMPAIGN   AGAINST   MALARIA   IN   ITALY    [Sect. 

very  numerous  persons  who,  being  without  any  kind  of  habita- 
tion, are  compelled  to  live  and  work  in  insalubrious  places. 


TABLE   IV 
The  Malaria  in  the  Army 


Year. 

Number 
of  men. 

Total 
number 
of  cases. 

Recurrent 
cases. 

Primary 
cases. 

Observations. 

1901 

1902 

1903 

1904 

1905  1 

1906 

1907 

1908 

189,848 

199,253 
206,468 
210,637 
204,745 
211,718 
202,320 
216,679 

49,94 

36,52 
24,14 
19,21 
23,00 
18,94 
12,46 
8,04 

17,85 
12,71 

13,90 

12,66 

7,76 

5,19 

6,28 
6,49 
9,05 
6,30 
4,50 
2,85 

Initiation  of  quinine  prophylaxis 
Continuation  of  quinine  prophylaxis 

,,                   ,,                   ,, 
Quinine  prophylaxis  becomes  extensive 

1,                   ,,                   I, 
„                   ,,                   ,, 

^  Year  of  periodic  epidemic  recrudescence. 

It  is  certain  that  it  is  much  better  to  be  able  to  live  in 
protected  houses,  and  to  make  preventive  use  of  quinine.  It 
is  precisely  this  mechanical  and  chemical  or  mixed  prophylaxis 
which  is  to-day  in  use  along  our  railways,  and  is  obligatory  for 

TABLE  V 
Malaria  along  the  Adriatic  Railways 


Days  of  mean 

Mean  of  days 

Year 

of  cases  of 

duration  of 

of  illness  lost 

Observations. 

malaria. 

cases  of 

malaria. 

per  person. 

1888-1905 

69-92 

7-88 

5-48 

Without  prophylaxis. 

1902 

44'93 

6-99 

3-12 

Mechanical  prophylaxis. 

1903 

30-32 

6-25 

1-89 

,,                     ,» 

1904 

33-10 

7-53 

2-48 

,,                     ), 

1905 

39'44 ' 

7-64 

3-01 

,,                     ,j 

1906 

27-65 

7.09 

3-39 

Mixed  prophylaxis. 

1907 

22-70 

8-58 

2-41 

M                                    ^, 

1908 

15-79 

9-67 

3-17 

"                                   ." 

1  Years  of  periodic  epidemic  recrudescence, 


49] 


RESULTS 


421 


the  contractors  of  public  works,  and  is  gradually  extending  also 
among  the  rural  administrations. 


TABLE   VI 
Malaria  among  the  Custom-house  Officers 


Year. 

Number  of 

Custom- 

House 

officers. 

Cases  of 

fever 
verified. 

Percentage. 

Observations. 

I  900-02 
1903 

1,738 

1,035 
222 

65-30 
1273 

Without  prophylaxis. 
Mechanical  prophylaxis. 

1904 
1905 

1,714 
1,721 

209 
187 

12-19 
10-86 

"                   " 
Mechanical   prophylaxis 

and  beginning  of 

1906 

1,614 

1x8 

7-31 

quinine  prophylaxis. 
Mechanical  and 
chemical  prophylaxis. 

1907 
1908 

1,642 
1,511 

7Z 
73 

4-50 
4-83 

,,                 ,, 
„                 » 

Thus  in  Italy  (where  we  have  employed  it  from  1899), 
Algeria  and  Russia,  it  has  been  proved  to  be  the  most  suitable 
method  for  guaranteeing  health  and  the  power  of  work  to  man 
even  in  the  most  desolate  malarious  regions. 

On  consulting  Tables  V  and  VI  it  appears  that  the  mean 
percentage  of  the  cases  of  malaria  along  the  Ex-Adriatic 
railways  has  diminished  from  69-92  to  15-79,  and  the  mean  of 
the  days  of  illness  from  5-48  to  3-17,  owing  to  the  gradual 
introduction  first  of  the  mechanical  and  later  of  the  mixed 
prophylaxis. 

Similarly,  amongst  the  Custom-house  officers  the  percentage 
of  malaria  has  fallen  from  65-30  to  4"83%. 

From  all  this  one  can  conclude  that  by  the  triple  alliance  of 
the  doctor,  drainage  and  agriculture,  it  is  possible  to  thwart  the 
most  formidable  enemy  of  our  country. 

It  is  necessary,  however,  for  the  doctor  to  proceed  with  the 
vanguard,  systematically  protecting  man  from  the  fevers  and 


422        THE  CAMPAIGN   AGAINST  MALARIA  IN   ITALY    [Sect. 

enabling  him,  therefore,  to  live  and  work  well  even  in  the  most 
unhealthy  places,  and  thus  break  that  old  vicious  circle  by 
means  of  which  man  could  not  live  on  the  land  because  it  was 
malarious,  and  it  could  not  have  been  rendered  healthy  because 
man  was  unable  to  live  on  it. 


III. — Legislation  Concerning  Malaria 

{a)  Laws  on  State  quinine. — These  laws  were  drafted  by 
us  on  a  very  solid  experimental  basis,  and  were  introduced 
into  our  sanitary  legislation  as  soon  as  their  necessity  and 
practicability  were  demonstrated. 

The  following  laws  were  promulgated  as  follows : — That  of 
23rd  December  1900  (State  quinine  on  sale  to  the  public  at  a 
minimum  price) ;  that  of  2nd  November  1901  (the  right  of 
workers  of  every  kind  to  have  gratuitously  the  State  quinine 
for  the  treatment  of  the  fevers  from  the  communal  doctors  at 
the  expense  of  the  respective  employers) ;  that  of  22nd  June 
1902  (concession  at  a  low  price  of  the  State  quinine  to  the 
communes,  charitable  institutions,  and  to  those  who  desire  or 
have  to  distribute  it  gratuitously  to  the  workers) ;  that  of 
25th  February  1903,  Article  3  (the  right  of  the  poor  to  have 
quinine  with  other  drugs  given  them  gratuitously  by  the 
communes  or  by  the  charitable  institutions) ;  and  finally,  that  of 
19th  May  1904  (the  right  of  workers  of  every  kind  to  have  it 
gratuitously  also  for  prophylaxis). 

These  laws,  demanded  by  new  social  duties,  necessarily 
must  have  clashed  with  many  private  interests. 

Parliament  had  the  notable  merit  of  passing  them  with 
wonderful  solicitude  and  agreement.  But  even  when  the  first 
law  was  promulgated,  we  saw  that  making  it  was  easy  enough, 
but  that  the  difficulty  rested  in  applying  it.  We  therefore  had 
to  watch  that  these  laws,  which  were  the  synthesis  of  our 
experience,  were  properly  applied. 

It  is  to  be  noted  also  that  every  fiscal  question  having  been 


49]  LEGISLATION  423 

set  aside,  the  net  profits  of  the  great  State  administration  (see 
Tables  V  and  VII)  went  entirely  to  lessen  the  causes  of 
malaria. 

Further,  one  can  loudly  proclaim  that  our  legislation  on 
State  quinine  has  not  only  a  scientific^  but  also  a  vioral  and  social 
purpose,  inasmuch  as  it  recognises  that  malaria  is  a  calamity 
connected  with  agricultural  work ;  and  it  wisely  imposes  upon 
the  employers  the  duty  of  preventing  the  damage  by  giving  the 
preventive  quinine  gratuitously  to  the  workers,  and  of  com- 
pensating them  by  giving  the  curative  quinine  also  gratuitously  ; 
and  to  the  relatives  of  employees  in  public  works  it  assures, 
besides,  the  payment  of  an  indemnity  in  cases  of  death  from  the 
pernicious  fevers. 

In  our  anti-malarial  legislation  the  mechanical  prophylaxis 
is  obligatory  solely  for  the  State  employees,  including  the 
railway  servants  who  inhabit  the  places  where  malaria  is  most 
severe.  To  the  private  persons  who  wish  to  adopt  it  for  their 
dependents  the  State  accords  premiums,  which  are  deducted 
from  the  profits  of  the  sale  of  the  State  quinine  (see  Table  VII). 

(^)  Laws  regarding  drainage. — Several  times  we  have  urged 
that  our  antiquated  laws  in  drainage  should  be  harmonised  with 
the  modern,  scientific  and  practical  views. 

We  have  succeeded  already  in  introducing  new  principles 
of  anti  -  malarial  hygiene  as  a  guide  in  the  planning  and 
execution  of  these  works. 

Formerly  it  was  believed  that  the  only,  or  at  least  the  best, 
mode  of  combating  the  fevers  was  sanitation  by  drainage,  and 
consequently,  in  the  supreme  interests  of  public  health,  expense 
was  no  object.  And,  in  fact.  New  Italy  has  spent  or  allotted 
upwards  of  500,000  lire  for  this  purpose,  which  works  out  at  no 
less  than  420  lire  (^16,  i6s.  8d.)  for  every  hectare  (2a.  ir.  35p.) 
drained.^  To-day,  however,  for  less  cost,  namely,  with  good 
quinine  and  healthy  houses  well  defended  from  mosquitos,  we 
can  protect  man  from  malaria. 

1  Compare  section  57.— R.  Ross. 


424        THE   CAMPAIGN   AGAINST   MALARIA  IN   ITALY    [Sect. 

At  the  present  day  we  know  how  to  spend  much  better 
than  in  the  past  these  many  millions  for  drainage,  which,  if 
well  employed,  would,  without  doubt,  render  the  land,  at  present 
barren  and  deserted,  definitely  prosperous  and  healthy. 

(c)  Laws  on  agrarian  sanitation.  —  Our  first  anti-malarial 
campaign  in  the  valley  of  the  Aniene  has  clearly  shown  that 
reoccupation  of  many  large  areas,  left  uncultivated  owing  to 
malaria,  can  now  be  easily  accomplished  ;  and  that  the 
labourers  can  be  kept  healthy  whilst  at  work  by  the  application 
of  modern  prophylactic  and  curative  measures. 

This  experiment  of  ours  has  inspired  several  others  to  adopt 
the  sanitation  of  the  Agro  Romano,  and  has  enabled  us  to 
encourage  and  direct,  with  the  sound  advice  of  the  medical 
hygienist,  the  great  undertakings  of  colonisation  arising  in 
different  parts  of  Italy,  and  destined  to  become  economic 
successes. 

IV. — Contribution  to  the  Organisation  of  the 
Campaign  against  Malaria 

We  invite,  above  all,  the  Government  to  set  the  good 
example  of  applying  the  new  methods  of  the  anti-malarial 
prophylaxis  to  all  the  workers  directly  and  indirectly  depending 
on  it.  At  present  the  majority  of  those  living  in  the  midst  of 
malaria  reap  the  benefit  of  the  new  laws  which  protect  them 
from  this  disease. 

Also  among  the  soldiers,  sailors  and  carabineers  the  new 
prophylaxis,  especially  the  chemical,  has  been  extending  from 
year  to  year. 

The  benefit  of  the  gratuitous  quinine  has  been  extending 
likewise  among  our  emigrants  who  depart  or  return  suffering 
from  malaria.  To  many  Italians  also  who  live  outside  Italy  in 
malarial  regions  it  has  been,  and  is,  distributed  by  the  Ministry 
of  Foreign  Affairs,  through  the  consuls  and  benefit  societies  ; 
and  to  make  it  better  known  and  appreciated,  gifts  of  quinine 


49]  DEMONSTRATION  CAMPS  425 

have  been  offered  and  accepted  by  other  States  which,  Hke 
Italy,  are  fighting  against  malaria. 

Directly  the  above-mentioned  law  of  19th  May  1904  was 
promulgated,  with  admirable  zeal  and  disinterestedness  our 
members  started  what  are  called  demonstration  camps  for  quinine 
prophylaxis  ;  and  we  have  become  more  and  more  convinced 
that  nothing  is  better  than  these  for  overcoming  the  apathy  and 
the  prejudices  of  our  people,  who,  living  for  ages  in  malarious 
places,  if  they  have  not  proved  it,  will  not  believe  it  possible  to 
protect  themselves  so  easily,  or  to  limit  the  damage  which 
they  are  accustomed  to  suffer,  and  to  believe  comes  from 
heaven. 

We  have  likewise  made,  and  continue  to  make,  a  wide 
propaganda  of  the  new  theories  and  laws  concerning  malaria. 

Of  manifestoes,  handbills,  bulletins,  reports,  extracts  from  the 
laws  and  regulations,  our  Society  has  distributed,  or  helped  to 
distribute,  about  2,000,000  copies  in  all. 

For  this  purpose  we  make  use  also  of  the  National  Associa- 
tion of  Parish  Doctors,  the  Ordini  del  sanitaria  the  Unione 
Magistrate  Italiana,  the  Associazione  dei  .Professori  di  Cattedre 
AmbiUanti  di  Agricoltiira,  the  Lega  NazionaU,  and  the  various 
local  Leagues  of  peasants  and  miners,  the  Camera  di  Lavoro, 
and  the  medical  and  lay  Press. 

Public  lectures  and  conversazioni  also  in  dialect,  repeated 
explanations  and  demonstrations,  have  not  been  neglected  by 
our  members,  especially  by  the  doctors  and  medical  students. 

Finally,  we  are  indebted  to  the  local  anti  -  malarial  com- 
mittees which  we  are  endeavouring  to  organise  throughout  the 
whole  of  Italy  for  an  active  propaganda  by  means  of  facts, 
publications,  lectures,  etc. 

V. — General  Results 

The  following  figures  enable  us  to  believe  and  hope  that  our 
labours  have  not  been  in  vain  : — 


426        THE   CAMPAIGN   AGAINST   MALARIA  IN   ITALY     [Sect. 


TABLE   VII 
State  Quinine  and  Mortality  from  Malaria 


Consumption  of  State 

Mortality  from 

QUIN 

INE. 

malaria. 

Net  profits 
of  administration 

of  State  quinine 

Financial 

Kilograms 

Solar 

Total 

in  lire. 

year. 

sold. 

year. 

deaths. 

1895 

16,464 

1896 

14,017 

1897 

11,947 

1898 

11,378 

1899 

10,811 

1900 

15,865 

1901 

13,861 

1902-3 

2,242 

1902 

9,908 

34,270 

1903-4 

7,234 

1903 

8,513 

183,039 

1904-5 

14,071 

1904 

8,501 

183,382 

1905-6 

18,712 

1905 

7,838 

293,395 

1906-7 

20,723 

1906 

4,871 

462,290 

1907-8 

24,351 

1907 

4,160 

700,062 

1908-9 

23,635 

1908 

3,463 

769,809 

From  the  foregoing  table  it  appears  that  the  annual  con- 
sumption of  State  quinine  has  progressively  increased  from 
2,242  to  about  23,000-24,000  kilograms,  and  that  in  these  seven 
years  the  mortality  from  malaria  has  progressively  diminished 
four-fifths. 

This  intimate  relation  between  the  progressive  increase  of  one 
and  the  progressive  diminution  of  the  other  cannot  honestly 
be  ignored  or  denied. 

In  fact,  from  1887  to  the  end  of  1895  upwards  of  15,000 
persons  died  annually  from  malaria.  From  1896  to  1902  an 
attenuation  began  (see  fig.  i),  but  still  13,000  in  media  died 
annually,  a  mortality  which  was  much  augmented  by  that  of 
the  period  of  the  recrudescence  in  1900.  On  the  contrary,  owing 
to  the  introduction  and  the  continuously  increasing  diffusion 
of  the  State  quinine,  the  mortality  from  year  to  year  has  rapidly 


49]  kESULTS  45^ 

fallen  to  less  than  4,000  victims,  and  the  characteristic  periodic 
recrudescences  have  no  longer  presented  themselves. 

Now,  who  can  deny  to-day  that  quinine  is  not  the  sovereign 
remedy,  and  that  only  those  die  from  malaria  who  do  not 
take  it  in  time  and  in  sufficient  quantity  ?  This  was,  and 
undoubtedly  is,  one  of  the  principal  causes  of  the  very  high 
mortality  in  the  poorest  regions  of  Italy,  because  they  are  the 
most  malarious,  and  they  are  the  most  malarious  because 
they  are  the  poorest. 

Well,  the  lessened  mortality  from  malaria  in  these  regions 
(see  fig.  2)  proves  to  us  that  the  sovereign  remedy  is  used  more 
and  more  among  the  poorest,  and  thus  our  legislation  has  begun 
to  reach  its  high  social  aim,  namely,  to  break  that  old  vicious 
circle  of  poverty  and  malaria.  If  one  considers,  besides,  that 
in  the  above  period  the  importation  of  quinine  into  Italy  by 
private  means  remained  more  or  less  the  same  (see  fig.  i,  middle 
part),  consequently  the  consumption  of  the  "  private "  quinine 
has  not  diminished,  while  that  of  the  State  now  equals  it,  and 
thus  the  total  consumption  of  quinine  is  almost  doubled  (see 
fig.  I,  middle  and  lower  parts). 

Regarding  the  efficacy  of  sanitation  by  drainage,  which 
necessarily  proceeds  very  slowly,  there  is  little  to  hope.  Also 
to  the  spontaneous  diminution  of  the  epidemy,  one  can  only 
assign  that  value  which,  according  to  fig.  2,  must  be  cal- 
culated on  the  basis  of  the  preceding  years. 

It  is  certain  that,  owing  to  the  State  quinine,  which  is  now 
legally  at  the  disposition  of  all,  no  person  ought  to  die  from 
malaria,  and  many  fewer  persons  ought  to  contract  it. 

We  remember,  however,  that  from  the  Maremma  downwards, 
including  the  Mezsogiorno  and  the  islands,  very  severe  malaria 
has  reigned  undisputed  for  centuries ;  and  during  the  five  years 
that  our  special  legislation  has  been  in  vogue,  and  in  spite  of 
the  efforts  of  the  administrative  powers,  there  are  still  many 
communes  which  do  not  furnish  quinine  in  sufficient  quantities, 


428        THE   CAMPAIGN    AGAINST   MALARIA   IN    ITALY     [Sect. 

not  even  for  the  treatment  of  the  fevers  ;  and  for  prophylaxis 
very  few  workers  receive  it  regularly  and  sufficiently. 

We  are,  however,  at  the  dawn  of  the  redemption  of  Italy 
from  this  scourge,  and  in  these  years  of  study  and  struggle^ 
our  Society,  one  can  say  without  boasting,  has  helped  to  indicate 
a  relatively  easy  path  to  the  desired  goal,  and  has  removed 
some  of  the  many  obstacles  to  success. 

Be  this  as  it  may,  after  having  taken  a  notable  part  in 
the  international  researches  into  the  cause  and  propagation 
of  malaria ;  after  having  studied  its  epidemy,  improved  the 
methods  for  combating  it,  and  introduced  new  ones  ;  enriched 
the  patrimony  of  the  pathological  knowledge;  prepared  new 
laws  and  endeavoured  to  improve  the  old  ones  ;  defended  the 
new  theories  and  laws  in  order  to  make  them  more  readily 
enter  into  the  customs  of  the  people,  and  enlarged  the  sphere 
of  action  for  all  Italy,  we  have  the  serene  consciousness  of 
having  performed  a  useful  duty  towards  our  country.  And 
we  cannot  but  be  delighted  that  outside  Italy,  and  following 
our  example,  other  attempts  are  being  carried  out,  that  anti- 
malarial campaigns  are  being  initiated,  and  that  other  societies 
or  leagues  similar  to  ours  have  been  formed  in  Algiers,  Corsica, 
Greece  and  Russia,  while  scientists  of  all  nations  visit  and 
appreciate  our  work.  Besides,  our  anti-malarial  legislation  has 
not  only  been  imitated  by  Austria,  and  by  France  for  Corsica 
and  Algiers,  but  has  also  been  wholly  adopted  by  Portugal, 
Greece,  Bulgaria,  Argentina.  .  .  .  All  this  enables  us  to  foresee 
the  formation  of  an  international  alliance  against  this  universal 
epidemy,  as  has  been  formed  already  against  other  epidemics.^ 

1  From  1893  to  July  1909,  we  had  at  disposal  for  our  work  only  about  90,000  lire. 

'^  On  the  unanimous  proposal  of  the  reporters  Ross,  Ruge,  Galli-Valerio,  Savas, 
and  Celli,  section  vii.  of  the  Fourteenth  International  Congress  of  Hygiene  and 
Demography  adopted  by  acclamation  the  following  resolutions  : — 

"The  Hygienic  Congress  urges  upon  Governments  of  malarious  countries  a  more 
active  campaign  against  malaria  by  means  of  all  the  methods  proposed  by  the  reporters 
to  the  Congress  on  this  subject,  and  particularly  advises  : 

"(i)  The  sale  by  Government  of  good  and  cheap  quinine  on  the  basis  of  the 
Italian  law ; 

"(2)  The  appointment  of  special  medical  commissioners  by  the  Governments  of 


49]  CONCLUSIONS  429 

VI. — Conclusions 

The  campaign  against  malaria  should  be  conducted,  two 
measures  acting  concurrently  : — 

(A)  The  one  directed  (a)  to  destroy,  or  at  least  (d)  render 
inoffensive,  the  mosquitos  which  inoculate  man  with  the 
parasite. 

(B)  The  other  directed  to  destroy  (a)  with  specific  means, 
(d)  with  general  means,  these  parasites  in  the  human  blood. 

(A — a)  The  extinction  of  mosquitos  can  be  obtained  by 
physical,  chemical  and  biological  means.  Frequently,  however, 
in  the  open  country,  the  extinction  is  interfered  with  by  the 
extent  to  which  the  reproduction  of  these  insects  is  assured  in 
Nature ;  and  while,  therefore,  it  requires  money  and  organisa- 
tion, it  can  have  practical  application  only  in  limited  districts, 
and  assisted,  where  possible,  by  better  and  more  extensive 
drainage. 

On  the  other  hand,  sanitation  by  drainage,  while  it  also 
requires  time  and  money,  which  fails  in  getting  rid  of  all  the 
surface  water  or  in  putting  it  in  movement,  does  not  succeed 
in  removing  the  local  conditions  necessary  to  the  life  of  the 
mosquitos,  and  even  when  it  can  succeed  agriculture  is  frequently 
opposed  to  it,  as  in  warm  climates  the  surface  water  is  utilised 
for  the  cultivation  of  rice,  etc.  Hence  it  is  that  sanitation  by 
drainage  by  itself  alone  is  not  always  efficacious  in  eradicating 
malaria  from  extensive  territories. 

{A — U)  It  is  relatively  more  easy  in  definite  circumstances 
to  render  the  mosquitos  inoffensive,  even  in  the  most  dangerous 
seasons  and  places,  by  keeping  them  away  from  persons  and 
houses  with  both  chemical  and  mechanical  means  {mechanical 
prophylaxis^. 

Be  this  as  it  may,  when  one  desires  to,  and  can  adopt  any 
means  whatever  directed  against  the  mosquitos,  one  must  never 

tropical  malarious  countries  to  direct  anti-malarial  measures  and  lo  superintend  the 
collection  of  the  malaria  statistics  for  those  Governments." 


430         THE  CAMPAIGN  AGAINST  MALARIA  IN  ITALY       [Sect. 

forget  that  in  many  parts  of  the  world  the  Anopheles  are  always 
present,  and  nevertheless  vialaria  either  has  disappeared  or  has 
become,  or  tends  to  become,  attenuated. 

{B — a)  The  destruction  of  the  malarial  parasites  in  the  human 
blood,  as  is  well  known,  can  be  obtained  by  means  of  the  specific 
remedy,  quinine. 

However,  it  is  certain  that  this  acts  in  inverse  proportion  to 
the  stage  of  development  of  the  parasites,  and  hence  it  is  that 
the  forms  destined  to  assure  the  conservation  and  propagation 
of  the  species  resist  most,  and  that  instead  the  sporozoites  resist 
but  slightly.  Therefore,  more  easily  and  more  readily  than 
with  the  curative  use,  one  obtains  the  specific  internal  disin- 
fection by  means  of  the  preventive  use  of  quinine,  and  of  its 
preparations  soluble  or  not  in  water,  administered  in  the  most 
agreeable  form,  and  preferably  in  average  doses  daily  (40  centi- 
grams per  die),  or  in  days  very  near  one  another,  in  order  to 
establish  a  perfect  mithridatism. 

With  this  preventive  treatment  extended  in  the  epidemic 
period  to  the  greatest  possible  number  of  inhabitants  of  a 
malarious  zone,  and  with  in  every  season  the  most  assiduous  and 
prolonged  quinine  treatment  of  the  malarial  patients,  one  will  see 
the  primary  infections  immediately  reducing  themselves  to  the 
minimun,  the  recurrents  reducing  themselves  much,  and  the 
pernicious  cases  and  the  cachexia  disappearing,  and  thus  from 
year  to  year  the  diminution  of  the  epidemy  among  the  respective 
populations  will  become  more  manifest  even  where  the  paludal 
and  the  local  anophelic  state  remains.  But  to  reach  all  this 
on  a  large  scale  it  is  indispensable  that  the  State  itself  should 
manufacture  the  quinine  preparations  in  order  to  sell  them  at 
the  miiiimum  price  or  to  distribute  them  gratuitously,  and  always 
in  the  more  agreeable  form  (comfits  or  chocolates,  etc.). 

Hygienic  education,  with  the  continuous  popular  propaganda 
and  anti-malarial  sanitary  organisation,  will  do  the  rest. 

Especially,  then,  with  the  quinine  prophylaxis  (eventually 
coupled  with  the  mechanical)  one  can  immediately,  where  and 


49]  CONCLUSIONS  431 

when  one  desires  it,  keep  man  healthy  even  on  very  unhealthy 
land,  and  thus  render  possible,  or  at  least  more  easy  and  prompt, 
the  drainage  and  agricultural  works  necessary  for  the  definite 
sanitation  of  even  very  vast  districts. 

{B — b)  Thus  more  promptly  and  without  the  mortality  of 
earlier  times  we  can  arrive  to-day  at  the  agrarian  sanitation^ 
and  colonisation  of  malarious  disti'icts,  or  establish  those  general 
means,  namely,  improving  the  alimentation,  clothing,  housing, 
education  of  man,  which  in  every  period  of  civilisation  augments 
the  organic  resistance  against  the  malarial  parasites,  and  by  this 
means  more  easily  subdue  malaria,  even  in  the  places  where 
anophelism  may  not  become  extinct. 

Evidently  neither  of  the  above-mentioned  series  of  measures 
for  combating  malaria  exclude  one  another,  but  can  mutually 
help  one  another,  and  ought  to  be  adopted  together  in  practice. 


By   const.   SAVAS 

Professor  of  Hygiene,  University  of  Athens.     Physician  to  H.M.  the  King 
of  Greece.      President  of  the  Greek  Anti-Malaria  League 

I 

50.  Anti- Malaria  Measures  in  Greece.^ — Greece  is  one  of 

those  countries  which  are  very  severely  scourged  by  malaria. 
The  information,  collected  by  the  Anti-Malaria  League  from 
all  the  mayors  of  the  kingdom,  and  from  a  great  number  of 
physicians,  proves  that  the  average  number  of  cases  of  the 
disease  throughout  the  kingdom  is  29%,  or,  in  other  words, 
out  of  a  total  population  of  2,631,952  inhabitants,  an  average 
of  770,0CK)  are  affected  by  the  disease  every  year.  It  happens, 
however,  that  in  some  years  the  number  of  cases  is  far  heavier. 
Thus,  for  example,  according  to  the  statistics  of  the  League, 
in  the  year  1905  more  than  half  the  inhabitants  of  the  country 
were  affected  by  malaria,  and  over  6,000  died  of  the  disease. 

Of  the  69  provinces  of  the  kingdom,  19  show  a  number  of 
cases  equal  to  over  40%  of  the  number  of  inhabitants,  and  of 
445  communes  only  29  are  free  from  the  disease,  whilst  the 
remainder  are  affected  in  a  greater  or  smaller  degree,  especially 
in  the  cases  of  59  communes  with  a  percentage  of  41  to  50%,  33 
with  51  to  60%,  23  with  61  to  70%,  18  with  71  to  80%,  and  2 
with  81  to  90%  ;  or  135  communes  (nearly  one-third  of  the  total 
number)  with  a  percentage  of  over  40%.  In  years  of  epidemic 
it  happens  that  in  many  communes  the  whole  of  the  inhabitants 
are  attacked  by  malaria. 

The  cause  of  this  great  frequency  of  malaria  is  not  only 
climatological,  but  is  also  due  to  the  existence  throughout  the 

1  Given  in  English  by  the  author.  — R.  Ross. 


Sect.  50]  PREVALENCE  433 

country  of  numerous  marshes  and  torrent  beds.  According  to  the 
information  collected  at  my  request  by  the  Government,  there 
are  in  Greece  639  marshes,  each  of  an  area  above  one  stremma 
(1,000  square  metres),  which  cover  together  from  84,657  to 
87,903  hectares,  or  846-879  square  kilometres.  As  the  whole 
kingdom  of  Greece  covers  an  area  of  60,000  square  kilometres, 
these  marshes  occupy  an  extent  varying  between  1/68  and  1/72 
of  the  whole  surface  of  the  kingdom.  In  addition  to  these 
marshes  Greece  is  full  of  small  marshes  of  under  1,000  square 
metres  in  extent,  and  of  torrent  beds  which  owe  their  existence 
to  the  widely  -  spread  deforestation  of  the  mountains,  due  to 
repeated  forest  fires  during  the  long  period  of  Turkish  domina- 
tion, as  well  as  during  the  Seven  Years'  War  of  Independence. 
These  torrent  beds  are  full  of  small  pools  which  ^xo.  par  excellence 
nurseries  of  Anophelines,  and  consequently  the  chief  cause  of 
malaria  in  Greece. 

Malaria  is  at  its  height  in  Greece  during  the  months  of  July, 
August  and  September,  and  commences  to  decline  in  October 
and  November;  but  relapses  continue  throughout  the  winter 
(from  December  to  March),  and  with  the  first  heat  of  May  the 
disease  recommences  its  baleful  activity. 

Malaria  has  from  prehistoric  times  been  the  scourge  of 
Greece.  The  classical  description  of  the  disease  in  the  works 
of  Hippocrates  is  well  known.  Information  concerning  malaria 
during  the  decline  of  ancient  Greece  is  lacking,  and  it  is  only 
after  the  birth  of  modern  Greece  that  descriptions  of  the  spread 
of  the  disease  again  appear.  Notwithstanding  the  fact  that 
these  descriptions  are  short  and  rare,  it  is  to  be  gathered  there- 
from that  the  disease  was  widely  prevalent,  especially  at  the 
commencement  of  the  establishment  of  the  new  state,  when  the 
cultivation  of  the  land  had  not  made  much  progress.  How- 
ever, after  the  reinstatement  of  law  and  order  the  population 
increased,  villages  and  towns  sprang  up,  the  cultivation  of  the 
land  spread  more  and  more,  and  measures  began  to  be  taken 
with  the  object  of  draining  many  of  the  smaller  and  some  of 

2  E 


434  ANTI-MALARIA  MEASURES   IN   GREECE  [Sect. 

the  large  marshes,  and  of  regulating  the  beds  of  the  torrents. 
By  these  measures,  and  at  the  same  time  by  the  application 
of  more  careful  medical  treatment  and  the  wider  use  of  quinine, 
malaria  commenced  to  decline,  and  there  is  no  doubt  that  the 
disease  is  now  not  only  less  common,  but  also  less  virulent  than 
formerly. 

This  relative  amelioration  is  not,  however,  due  to  a 
systematic  campaign  against  this  disease,  but  to  the  above- 
mentioned  causes  which  came  about,  so  to  say,  automatically 
with  the  progress  of  civilisation.  The  methodic  and  systematic 
fighting  of  malaria  only  commenced  when,  in  January  1905, 
I  founded  the  Anti  -  Malarial  League,  which  laid  the  first 
scientific  and  practical  basis  of  the  campaign  against  malaria, 
and  met  with  an  extremely  favourable  reception  in  all  parts 
of  the  country.  We  propose  hereinafter  to  give  a  concise 
description  of  the  general  measures  which  have  been  taken 
by  the  Government  and  by  the  League,  as  well  as  of  those 
special  sanitary  operations  which  have  been  executed  either 
by  the  Government  or  by  the  League  or  by  different  com- 
panies. 

The  general  measures  include  the  popularisation  of  the 
ideas  now  prevalent  regarding  the  manners  in  which  malaria 
is  caused  and  repressed,  and  the  undertaking  of  the  supply 
and  sale  of  quinine  by  the  Government. 


II 

Propagation  of  scientific  knowledge  concerning  malaria.  — 
Two  years  previous  to  the  foundation  of  the  League  I  issued 
a  pamphlet.  Instructions  for  Use  in  Combating  Malaria,  which 
was  printed  at  the  cost  of  the  Government  and  distributed  in 
thousands  amongst  all  the  physicians,  engineers  and  mayors 
of  the  kingdom.  On  the  establishment  of  the  League,  one 
of  its  first  cares  was  the  publication  of  a  small  pamphlet  of 
sixteen    pages    containing    short    instructions    regarding   the 


5o]  PUBLIC  INSTRUCTION  435 

causes  and  prevention  of  malaria.  Forty  -  five  thousand  of 
these  pamphlets  have  been  distributed  amongst  not  only  all 
the  local  authorities,  but  also  many  of  the  educated  inhabitants, 
especially  the  schoolmasters,  who  have  been  instructed  by 
the  Ministry  to  explain  the  questions  to  their  pupils.  Last 
year,  too,  the  Government  printed  300,000  copies  of  a  leaflet 
containing  the  decalogue  of  malaria.  This  leaflet  was  dis- 
tributed amongst  the  pupils  of  the  schools,  who,  after  the 
teachers  had  explained  the  instructions  to  them,  were  told 
to  give  them  to  their  parents.  At  the  same  time  of  late 
years  the  daily  press  and  the  periodicals  of  the  whole  country 
have  repeatedly  published  illustrated  articles  on  the  part  of 
members  of  the  League  respecting  the  causes  and  prevention 
of  malaria.  In  addition,  some  hundred  of  the  leading  physicians 
of  the  country  were  invited  to  Athens  by  the  League.  These 
gentlemen  remained  for  two  days  in  Athens,  and  consulted 
with  the  chief  members  of  the  League  regarding  the  ways 
and  means  of  combating  malaria  in  Greece,  and  heard  us 
explaining  the  latest  scientific  discoveries  in  this  connection. 
On  their  return  to  their  homes  they  acted  as  apostles  of  the 
anti-malaria  movement,  both  amongst  the  other  local  medical 
men,  the  authorities  and  the  people,  visiting  the  chief  malarious 
districts  of  the  country,  and  both  pointing  out  the  absolute 
need  of  the  preventive  use  of  quinine,  searching  out  the  small 
pools  which  serve  as  nurseries  of  Anophelines,  and  applying, 
wherever  possible,  the  various  sanitary  measures  recommended 
in  the  work  of  Professor  Ronald  Ross,  "  Mosquito  Brigades," 
which  has  been  translated  into  Greek,  and  printed  at  Govern- 
ment expense  and  distributed  gratis. 

The  importance  of  combating  malaria  and  the  manner  of 
so  doing  have  repeatedly  been  explained  to  the  engineers  and 
heads  of  the  Agricultural  Schools,  and  especially  to  school- 
masters, whenever  they  have  been  assembled  for  educational 
purposes  by  the  Government  inspectors. 

The    League    has    also    approached    the   rich   landowners, 


436  ANTI-MALARIA   MEASURES    IN   GREECE  [Sect. 

furnishing  them  with  printed  instructions  and  pointing  out 
the  necessary  sanitary  measures  in  connection  with  the  pools 
on  their  estates,  and  urging  them  to  disseminate  and  apply 
general  measures  for  the  prevention  of  malaria. 

Conjointly  with  measures  for  the  popularisation  of  the 
methods  of  combating  malaria,  the  League  has  also  attended 
to  the  collection  of  local  information  concerning  the  disease. 
Official  Health  Statistics  are  issued  in  Greece  only  in  the 
case  of  the  twelve  chief  towns  of  the  kingdom,  the  population 
of  which  together  amounts  to  430,000,  and  they  are  confined 
to  the  number  of  deaths,  whilst  with  regard  to  the  frequency 
of  disease  and  the  mortality  in  the  rest  of  the  kingdom  no 
official  statistics  are  to  be  had.  We  have  consequently  deemed 
it  right  to  apply  for  information  to  all  the  physicians  of  the 
country  regarding  the  number  of  cases  of  malaria  in  the 
districts  in  which  they  practise.  This  information  refers  to 
the  periods  of  the  commencement,  the  height  and  the  decline 
of  the  disease,  to  the  ascertainment  of  the  percentage  of  cases 
among  the  inhabitants,  both  absolute  and  relative  to  past  years, 
and  to  certain  other  questions.  We  succeeded  in  collecting 
information  of  this  kind  relating  to  five  years.  Several  of  the 
physicians  drew  up  at  the  same  time  lengthy  reports  concern- 
ing malaria  in  their  provinces,  and  respecting  the  marshes  in 
the  district,  with  the  measures  by  which  the  disease  may  be 
stamped  out.  At  the  request  of  the  League  the  Government 
instructed  all  the  local  mayors  to  submit  reports  as  to  the 
number  of  cases  in  each  commune,  and  the  marshes  existing 
therein.  A  complete  epidemiological  chart  of  the  frequency 
of  the  malaria  in  Greece  was  thus  drawn  up.  This  plentiful 
material  was  published  by  the  League  in  three  bulky  volumes, 
which  also  contain  the  results  of  a  similar  work  undertaken 
in  the  island  of  Crete  by  our  League.  We  are  of  the  opinion 
that  the  collection  of  information  of  this  kind  is  not  merely 
valuable  for  the  sake  of  the  information  itself,  but  also  in  that 
it  incites  physicians,  mayors,  engineers  and  people  generally 


5o]  STATE  QUININE  437 

speaking  to  turn  their  attention  to  the  spread  of  the  disease 
and  the  detriment  caused  thereby,  keeps  them  in  continual 
intercourse  with  us  and  the  question  always  on  the  tapis, 
undoubtedly  resulting  in  measures  being  taken  with  a  view 
to  combat  the  disease. 


III 

The  State  Quinine. — In  view  of  the  splendid  results  achieved 
in  Italy  by  the  assumption  by  the  Government  of  the  provision 
and  sale  of  quinine,  the  League  has  recommended  a  similar 
measure  for  Greece.  We  were  also  induced  to  take  this  view 
by  the  fact  that  considerable  abuse  took  place  in  connection 
with  the  sale  of  quinine,  which  is  sold  in  Greece  not  only  by 
chemists  but  also  by  grocers.  This  quinine  not  only  is  some- 
times of  bad  quality,  but  is  often  adulterated  with  foreign 
substances,  besides  which  it  is  far  from  rarely  sold  underweight 
to  customers,  whilst,  to  crown  all,  it  is  sold  at  a  very  high 
price,  so  as  to  render  the  frequent  use  of  quinine  by  the 
poorer  classes  beyond  their  means.  As  a  means  of  putting  a 
stop  to  these  abuses  the  League  appealed  to  the  Government 
and  the  Chamber,  setting  forth  the  harm  done  by  malaria, 
and  at  the  same  time  pointing  out  the  means  of  remedying  the 
evil,  the  foremost  of  which  is  considered  to  be  the  undertaking 
by  the  Government  of  the  provision  and  sale  of  quinine.  At 
the  same  time  the  League  published  the  report,  which  was 
sent  at  our  request  by  the  Liverpool  Tropical  School,  followed 
by  a  draft  of  a  bill  concerning  quinine,  together  with  an 
explanatory  report,  and  finally  a  translation  of  the  Italian 
laws  regarding  the  combating  of  malaria. 

The  Chamber  refused  to  accept  the  principle  of  a  monopoly 
of  quinine  proposed  by  the  League,  and  on  the  15th  of 
December  1907  passed  a  bill  similar  to  the  Italian  quinine 
law.  According  to  this  the  Government  acquires  the  right 
to  order  and  to  sell  any  of  the  salts  of  quinine  recommended 


438  ANTI-MALARIA    MEASURES    IN    GREECE  [Sect. 

by  the  Royal  Sanitary  Council.  The  order  is  given  by  the 
Minister  of  Finance  on  the  basis  of  tenders  (except  in  case 
the  quinine  is  purchased  from  foreign  State  institutions),  and 
fixed  upon  on  each  occasion  by  the  Sanitary  Council.  The 
sale  of  quinine  is  made  by  the  Chemical  Laboratory  attached 
to  the  Ministry  of  Finance,  by  the  Public  Treasuries,  post 
and  telegraph  offices,  educational  functionaries,  and  by  other 
authorities  chosen  by  Royal  Decree.  The  State  sells  quinine 
at  cost  price.  It  is  sold  retail  to  the  public  by  chemists,  grocers 
and  other  merchants,  who  derive  a  small  profit  therefrom.  In 
the  case  of  bisulphate  of  quinine  the  law  demands  that  the 
retail  price  per  gramme  shall  not  exceed  lo  lepta  (centimes). 
The  price  of  other  salts  of  quinine  is  fixed,  as  occasion  arises, 
by  Royal  Decree.  The  importation  and  sale  of  quinine  is  not 
prohibited  by  this  law,  but  such  commercial  quinine  will  be 
examined  chemically  at  the  custom  houses,  and  will  only  be 
allowed  to  enter  provided  the  quality  is  equal  or  superior  to 
that  of  the  State.  Heavy  penalties  are  prescribed  for  persons 
selling  State  quinine  or  the  commercial  article  at  prices  above 
that  fixed,  adulterating  or  selling  adulterated  quinine,  smuggling 
quinine  into  the  kingdom  or  selling  quinine  underweight.  The 
law  also  obliges  such  communes  as  are  severely  scourged  by 
malaria  to  enter  in  their  budgets  an  amount  destined  for  the 
purchase  of  State  quinine  to  be  distributed  gratis  to  the  poor 
of  the  commune. 

After  the  publication  of  this  law  Greece  requested  the 
Italian  Government  to  supply  the  requisite  amount  of  quinine 
out  of  that  prepared  for  the  latter.  The  Italian  Government 
was  kind  enough  to  consent,  and  the  Greek  Government  now 
receives  from  Italy  bisulphate  and  hydrochlorate  of  quinine  in 
tablets  of  o-20  gramme,  packed  in  boxes  containing  ten  glass 
tubes,  each  of  five  tablets.  The  contents  of  the  box,  together 
with  the  price  and  the  above-mentioned  penalties,  are  printed 
on  the  outside  label.  The  glass  tubes  are  wrapped  in  paper 
containing  full  instructions  for  the  use  of  the  quinine,  in  which, 


so]  STATE  QUININE  439 

in  the  case  of  adults,  the  dose  prescribed  is  five  tablets 
(i  gramme)  per  diem  for  a  week,  followed  by  two  tablets  per 
diem  during  the  following  two  months.  The  inhabitants  of 
marshy  districts  are  recommended  as  a  preventive  measure 
to  take  two  tablets  every  day  from  the  end  of  May  to  the 
beginning  of  November.  The  proper  dose  for  children  is  also 
given  in  these  instructions.  Besides  these  tablets  the  Italian 
Government  supplied  phials  for  hypodermic  injections,  con- 
taining a  solution  of  quinine  made  up'  according  to  the 
prescription  of  Gaglio  (phials  of  i  gramme  solution  contain 
0'40  hydrochlorate  of  quinine  and  0'20  ethyl  urethane).  These 
injections  have  an  alkaline  reaction,  and  are  painless,  whilst 
they  cause  neither  necrosis  nor  callosity,  and  are  very  easily 
absorbed.  We  were  also  supplied  with  chocolates  of  tannate 
of  quinine,  each  double  chocolate  containing  0'85  gramme  of 
tannate  of  quinine,  or  0'30  gramme  of  pure  anhydrous  quinine 
(cioccolattini). 

This  State  quinine,  which  is  sold,  not  only  by  chemists,  but 
also  by  merchants  of  every  kind,  found  its  way  with  astonish- 
ing rapidity  all  over  the  kingdom.  Ten  thousand  kilogrammes 
of  quinine  in  tablets  and  60,000  boxes  of  chocolates  were  sold 
in  the  first  year  after  its  introduction,  which  ended  in  September 
last.  This  is  a  large  quantity  if  it  be  remembered  that  the 
average  sale  of  quinine  by  merchants  during  the  previous 
seven  years  amounted  to  6,000  kilogrammes,  and  that  besides 
this  State  quinine,  a  further  amount  of  quinine  derived  from 
other  sources  was  sold  by  retailers.  The  quantity  thus  sold 
is  not  yet  known  to  us. 

The  League  has  especially  endeavoured,  by  means  of  various 
publications  and  by  circulars  addressed  to  physicians,  to 
promote  as  much  as  possible  the  preventive  use  of  quinine. 
We  are,  however,  afraid  that  the  achievement  of  this  object 
will  be  difficult,  as  the  majority  of  people  will  only  take  quinine 
after  being  attacked  by  malaria. 

We  have  now  given  a  description  of  the  general  measures 


440  ANTI-MALARIA   MEASURES   IN   GREECE  [Sect. 

employed  against  malaria,  and  shall  next  describe  a  few 
of  the  sanitary  measures  undertaken  in  certain  districts  of 
the  country. 


IV 

Anti-malaria  measures  in  the  plain  of  Marathon.  —  After 
endeavouring  by  every  means  to  popularise  the  knowledge  of 
the  mode  of  fighting  malaria,  the  League  considered  it  to  be 
its  duty  to  provide  a  practical  example,  by  undertaking  at 
least  one  definite  work  of  the  kind,  with  the  object  of  con- 
vincing people  of  the  efficacy  of  the  measures  recommended. 
It  was  also  necessary  for  the  conditions,  which  are  indis- 
pensable for  the  achievement  of  such  work  in  Greece,  to  be 
studied  on  the  spot.  With  this  object  in  view  Marathon  v/as 
chosen  as  the  field  of  action. 

The  plain  of  Marathon  lies  on  the  east  coast  of  Attica, 
at  a  distance  of  30  kilometres  from  Athens,  and  is  11  kilo- 
metres in  length.  It  is  famous  in  connection  with  the  battle 
fought  in  490  B.C.  between  the  Greeks  and  Persians,  and  con- 
tains a  few  villages,  amongst  which  is  that  of  Marathon,  the 
capital  of  the  commune.  The  northern  part  of  the  plain  is 
traversed  by  a  torrent  which  runs  close  to  the  villages  of 
Marathon  and  Bey,  whilst  at  the  north-east  extremity  of  the 
plain  there  are  extensive  marshes.  The  following  villages  and 
hamlets  are  situated  in  this  plain : — the  village  of  Marathon 
with  1,200  inhabitants;  that  of  Bey  with  150  inhabitants,  at 
a  distance  of  i  kilometre  from  Marathon  ;  that  of  Lower 
SouH  with  160  inhabitants,  at  a  distance  of  5  kilometres; 
besides  these,  eight  hamlets  are  scattered  over  the  plain,  with 
173  inhabitants  in  all.  The  total  population  of  the  plain 
thus  amounts  to  some  1,680  souls,  most  of  whom  are  engaged 
in  agriculture  and  vine-growing,  and  a  few  in  poultry  and  stock 
farming,  and  thus  spend  the  greater  part  of  their  time  in  the 


so]  MARATHON  441 

plain,   returning   to   their  houses   to   spend  the  night,  with    a 
very  few  exceptions. 

The  inhabitants  of  the  plain  of  Marathon  are  extremely 
subject  to  malaria.  An  examination,  conducted  in  October 
1906,  of  the  pupils  of  the  local  school,  show  that  100% 
suffered  from  an  enlarged  spleen.  In  May  1907,  1,216  persons 
were  examined,  and  1,031,  or  8479^,  suffered  from  fever  during 
the  previous  summer.  These  observations  coincide  with  the 
reports  of  the  Marathon  doctors,  one  of  whom  put  the  number 
of  cases  of  malaria  in  1906  at  90%,  and  the  other  at  80%. 
Owing  to  the  great  prevalence  of  malaria  the  inhabitants,  at 
the  commencement  of  our  work  of  sanitation,  were  pale  and 
sallow,  and  their  skin  dried  up,  whilst  they  appeared  exhausted 
and  incapable  of  work  owing  to  frequent  attacks  of  fever.  In 
many  cases  the  spleen  was  enormous,  and  reached  the  pubic 
symphysis.  According  to  the  evidence  of  the  local  physicians 
the  mortality  was  very  great,  not  merely  among  the  children, 
but  also  among  adults,  whilst  death  occurred  not  only  from 
pernicious  fevers,  but  to  a  great  extent  from  pneumonia,  which 
is  one  of  the  commonest  diseases  of  the  place.  Mortality  was 
so  common  amongst  adults  that  three-fifths  of  the  inhabitants 
had  been  married  a  second  time,  whilst  persons  of  over  sixty 
years  of  age  were  rarely  found,  whereas  longevity  is  common 
in  the  healthy  villages  of  Greece. 

Throughout  the  whole  plain  of  Marathon  stagnant  waters 
were  found  in  the  bed  of  the  torrent,  which  flows  near  the 
two  villages,  in  the  two  large  marshes,  and  in  small  pools 
between  the  two  marshes. 

In  this  stagnant  water  we  invariably  found  larvae  of 
Anopheline  mosquitos.  Both  in  the  bed  of  the  torrent  and 
the  houses  of  the  villages  of  Marathon  and  Bey  the  Anopheles 
superpictus  was  especially  noticeable,  whilst  in  the  marsh  of 
Lower  Souli  a  large  number  of  larvae  of  Anopheles  claviger'^ 
was   found,  together   with   a  small  number  of  bifurcatus,  and 

^  A.  rnaculipennis  Meig. 


442  ANTI-MALARIA   MEASURES    IN   GREECE  [Sect. 

in  the  houses  of  this  village  a  large  number  of  Anopheles 
claviger  was  remarked.  In  the  other  marsh,  which  is  situated 
at  some  distance  from  the  villages,  repeated  examination 
brought  to  light  a  very  small  number  of  the  larvae  of  Anopheles 
supeipictus  and  claviger.  In  all  the  other  distant  pools  through- 
out the  plain  only  Anopheles  claviger  was  discovered,  but  in 
large  quantities.  The  chief  source  of  the  malaria  in  the 
villages  of  Marathon  and  Bey  was  therefore  concluded  to  be 
the  adjacent  torrent,  and  that  of  the  village  of  Lower  Souli,  the 
neighbouring  marsh.  The  inhabitants  of  the  hamlets  in  the 
plain  were,  of  course,  infected  by  mosquitos  from  the  other  pools. 

The  first  larvae  of  Anopheles  were  remarked,  in  the  case 
of  the  year  1907,  at  the  end  of  April,  and  in  1909  at  the 
commencement  of  May. 

The  work  of  sanitation  was  carried  on  at  Marathon  during 
three  successive  years,  and  only  during  the  summer  and  the 
commencement  of  the  autumn.  In  the  year  1907  we  com- 
menced on  1st  May  and  continued  until  November,  whilst 
in  1908  and  1909  we  carried  on  operations  from  ist  June  to 
20th  October.  The  staff  engaged  in  this  work  was  composed 
in  1907  of  one  physician  and  one  medical  student  as  assistant, 
both  despatched  from  Athens  for  the  purpose,  whilst  in  1908 
we  employed  one  physician  and  two  medical  students,  and 
in  1909  only  one  physician  without  any  assistant.  The 
physician  and  his  assistants  were  installed  in  a  small  house 
in  the  village  of  Marathon,  where  they  set  up  a  microscopical 
laboratory,  and  a  pharmacy  which  included  a  certain  number 
of  absolutely  indispensable  drugs  besides  quinine.  Patients 
received  advice  and  treatment  gratis.  Only  sufferers  from 
malarial  diseases  were  admitted,  all  other  applicants  being 
referred  to  the  village  physicians. 

The  work  was  performed  in  the  following  manner : — In  the 
first  place,  the  names  of  the  inhabitants  of  the  villages  were 
entered  in  a  special  register,  together  with  their  age,  and  any 
enlargement  of  the  spleen  stated,  as  well  as,  in  many  cases, 


5o]  MARATHON  443 

the  result  of  the  microscopical  examination  of  their  blood. 
The  inhabitants  were  next  divided  into  as  many  sections  as 
there  were  physicians  of  the  League,  and  each  of  these  doctors 
took  care  of  the  inhabitants  who  fell  in  his  section.  Patients 
complaining  of  attacks  of  malaria  were  examined  as  regards 
both  their  spleens  and  blood,  and,  if  proved  to  be  so  suffering, 
were  subjected  to  the  proper  treatment  as  described  below. 
As  a  means  of  facilitating  our  work  several  lectures  were  given 
by  our  physicians  to  the  people,  and  by  the  teachers  to  their 
pupils,  explaining  the  plan  of  the  League  to  render  healthy 
the  plain  of  Marathon,  and  other  related  details.  At  the 
commencement  of  our  work  the  peasants  showed  some  dis- 
trust. Later  on,  however,  when  they  were  convinced  of  our 
good  intentions,  they  willingly  agreed  to  undergo  the  treat- 
ment proposed  by  us,  and  showed  considerable  gratitude  at 
being  liberated  from  the  terrible  scourge  which  had  from  time 
immemorial  tormented  their  country.  We  proceeded  in  the 
work  of  sanitation,  firstly  by  destroying  the  larvae  in  the 
torrent  bed,  and  secondly,  by  administering  quinine,  which 
was  purposely  distributed  in  a  different  manner  in  each  of 
the  three  years.  In  order  to  prevent  the  development  of 
Anophelines  in  the  torrent  bed  the  water  thereof  was  drawn 
off  in  a  narrow  channel  so  as  to  produce  a  more  rapid  flow, 
whilst  all  pools  were  treated  every  ten  days  with  petroleum, 
which  generally  is  provided  by  the  Government,  mixed  with 
tar,  at  a  minimum  price  for  the  purpose  of  destroying  locusts. 
In  this  part  of  our  work  we  received  valuable  aid  from  the 
teacher  of  the  village,  who  indefatigably  attended  to  the  carry- 
ing out  of  this  measure  with  the  help  of  his  young  pupils. 

The  quinine  was  given  therapeutically  throughout  the  three 
years,  and  preventively  only  during  the  first  and  the  second 
year.  Sulphate  and  hydrochlorate  of  quinine  were  given  thera- 
peutically to  patients  of  ten  years  of  age  at  the  rate  of  i  to  I'S 
grammes  per  diem  for  eight  successive  days,jn  the  case  of  those 
who   had   suffered   one   or   more   attacks,   or   in   whose   blood 


444  ANTI-MALARIA    MEASURES    IN    GREECE  [Sect. 

parasites  were  detected.  Children  under  ten  were  treated 
therapeutically  with  a  quantity  of  quinine  proportionate  to 
their  age,  z>.,  from  eight  to  ten  years  of  age,  o*8o  gramme, 
from  six  to  eight,  0'6o,  and  from  four  to  six,  040  gramme. 
Children  under  four  were  given  tannate  of  quinine  either  in 
powder  or  in  chocolate ;  during  the  first  year  the  sulphate  or 
hydrochlorate  of  quinine  was  given  in  wafers,  and  during  the 
two  remaining  years  in  the  shape  of  tablets. 

In  addition  to  the  therapeutic  employment  of  quinine  during 
the  first  year  we  also  used  the  drug  preventively.  With  this 
object  we  gave  out  quinine  to  all  the  inhabitants,  irrespective 
of  whether  they  suffered  from  fever  or  not,  according  to  the 
method  of  Koch  as  modified  by  the  Italians;  i.e.,  i  gramme 
of  quinine  per  diem  for  two  successive  days  in  the  week  to 
those  above  the  age  of  ten,  and  a  proportionate  quantity  to 
the  children,  i.e.,  075  gramme  in  the  case  of  those  aged  from 
eight  to  ten,  0*50  in  the  case  of  those  aged  six  to  eight,  and 
0'25  gramme  to  those  of  four  to  six.  In  the  case  of  infants 
below  the  age  of  four  they  were  given  euquinine  or  chocolate 
with  tannate  of  quinine.  The  quinine  was  given  out  to  the 
pupils  every  Thursday  and  Friday  at  the  school,  and  every 
Saturday  and  Sunday  to  the  other  peasants.  It  must,  how- 
ever, be  confessed  that  this  preventive  method  did  not  prove 
to  be  practically  applicable,  as  the  peasants,  healthy  men 
in  other  respects,  who  worked  on  week-days  in  the  fields, 
found  such  large  doses  very  annoying,  owing  to  the  con- 
sequent singing  in  the  ears  and  other  discomfort,  especially 
on  Sundays,  the  only  day  in  the  week  on  which  they  can  rest 
and  amuse  themselves.  These  large  doses  also  hindered  them 
in  their  work  during  the  week.  Several  of  the  pupils  suffered 
so  much  from  giddiness  and  drowsiness  after  taking  quinine 
that  they  were  unable  to  attend  to  their  lessons. 

Out  of  the  1,680  inhabitants  only  1,544  went  through  this 
preventive  treatment  in  1,252  cases.  Unfortunately,  all  would 
not  continue  a  regular  course,  but  the  figures  given  hereunder 


so]  RESULTS  445 

show  the  results  of  the  preventive  treatment  according-  to  the 
length  of  application. 

Of  Gj  persons  who  took  quinine  during  21-24  weeks  none 
were  attacked  by  malarial  fevers. 

Of  145  persons  who  took  quinine  during  16-20  weeks  30 
were  attacked,  or  20'6%. 

Of  220  persons  who  took  quinine  during  11-16  weeks  103 
were  attacked,  or  48*6^. 

Of  820  persons  who  took  quinine  irregularly  during  i-io 
weeks  464  were  attacked,  or  56'5%. 

It  follows,  therefore,  that  out  of  1,252  persons  taking  quinine 
only  597,  or  47'6%,  suffered  from  malaria.  It  must  here  be  added 
that  in  the  surrounding  villages,  which  were  not  included  in  our 
sphere  of  action,  malaria  was  prevalent  to  a  very  great  extent, 
so  that  we  may  consequently  consider  that,  without  our  inter- 
vention, we  should  have  had  the  usual  number  of  cases  of 
malaria  at  Marathon  too,  or  from  80  to  90%,  if  not  more. 

An  investigation  carried  out  in  May  1907  showed  57^  of 
enlarged  spleen  out  of  125  pupils  of  either  sex,  and  of  39/^  out 
of  752  adult  inhabitants.  After  the  conclusion  of  the  sanitary 
work,  or  at  the  end  of  October,  an  examination  of  1 10  pupils 
showed  only  35^  with  enlarged  spleens,  and  of  509  adults,  25/^. 
The  proportion  of  cases  of  enlarged  spleen  was  therefore  less 
at  the  end  of  the  summer  season,  thanks  to  the  sanitary 
measures,  without  which,  it  will  be  easily  understood,  it  would 
certainly  have  been  greater.  In  the  whole  district  under  our 
control  one  person  died  of  pernicious  fever  and  three  persons 
of  blackwater  fever.  All  three  were  treated  by  the  local 
physicians.  In  1905,  according  to  information  furnished  by 
the  doctors,  seven  persons  died  of  malarial  diseases. 

During  the  summer  of  1908  we  changed  the  manner  of 
giving  out  quinine,  and  adopted  the  Italian  preventive  system  ; 
ix.y  between  ist  June  and  20th  October  we  gave  out  every  day 
two  tablets  (0"40  gramme)  in  the  case  of  persons  above  the  age 
of  ten,  and  one  only  (0*20  gramme)  in  that  of  children  below 


446  ANTI-MALARIA   MEASURES    IN   GREECE  [Sect. 

the  age  of  ten  down  to  the  age  when  swallowing  the  tablets 
was  not  possible.  In  the  case  of  infants  unable  to  swallow  the 
tablets  we  gave  chocolate  with  tannate  of  quinine,  as  furnished 
by  the  Italian  Government.  As,  however,  we  only  had  a  small 
stock  of  these,  we  confined  their  use  to  the  cases  of  twenty-six 
infants,  and  for  a  short  period  only.  It  may  therefore  be  said 
that  the  preventive  method  was  not  applied  in  the  case  of 
infants  of  under  three  years. 

Out  of  1,306  inhabitants  of  the  villages  of  Marathon  and 
Bey  only  fifty-six  (4'28%)  suffered  from  malaria  during  the  whole 
summer.  If,  however,  we  deduct  from  these  two  pregnant 
women,  who  took  no  quinine  from  fear  of  causing  a  miscarriage, 
twenty-one  children,  who  only  took  quinine  irregularly  owing  to 
the  lack  of  "  cioccolattini,"  one  who  came  infected  from  Athens, 
one  who  suffered  from  urticaria  owing  to  the  use  of  quinine,  and 
one  of  the  local  doctors,  who  refused  to  undergo  the  preventive 
treatment,  together  with  four  persons  who  were  infected  at  the 
commencement  of  our  work,  there  remain  only  twenty-six  cases 
of  malaria,  and  the  percentage  is  reduced  to  i'99%. 

It  is  to  be  remarked  that  in  the  surrounding  villages  the 
malaria  was  very  severe. 

There  died  only  one  child  of  those  who  regularly  took 
quinine,  of  a  disease  which  the  local  doctor  who  was  attending 
it  described  as  pernicious  fever,  without,  however,  parasites 
being  discovered  in  either  of  two  examinations  which  were 
made  of  the  blood. 

With  regard  to  the  examination  of  the  spleen  of  the  pupils 
this  showed  an  enlarged  spleen  in  3 1  to  43%  at  the  beginning  of 
June,  and  7'40%  at  the  end  of  October. 

This  method  of  giving  out  quinine  was  welcomed  by  the 
inhabitants,  who  both  remarked  the  beneficent  results  and 
experienced  no  ill-effects,  and  showed  great  willingness  in 
adopting  it. 

During  the  third  and  last  year  of  our  work  at  Marathon 
(the  summer  of  1909)  we  neither  took    measures  against  the 


so]  COST  447 

larvae  of  the  Anopheles^  neither  did  we  give  out  quinine  for 
preventive  treatment,  but  confined  ourselves  to  the  therapeutic 
employment  of  the  drug,  according  to  the  Austrian  treatment 
adopted  in  Dalmatia.  We  therefore  gave  out  quinine  only  to 
those  who  had  suffered  distinct  attacks  of  malaria,  and  whose 
blood  contained  the  parasite.  The  quinine  was  given  out  in 
the  following  way  : — one  gramme  of  State  quinine  every  day  for 
a  week,  followed  by  0*40  gramme  every  day  for  two  months, 
to  patients  of  the  age  often  and  above.  In  the  case  of  children 
from  eight  to  ten  years  of  age,  o*8o  gramme  every  day ;  from 
six  to  eight,  0'6o  gramme ;  from  four  to  six,  0*40  gramme  in 
each  case  for  a  week,  followed  by  0*20  gramme  every  day  for 
two  months.  In  the  case  of  children  below  the  age  of  four 
years  State  chocolate  with  tannate  of  quinine  was  given.  The 
result  of  this  treatment  was,  that  out  of  the  1,312  inhabitants 
only  176,  or  I3"4i%,  suffered  from  malarial  attacks,  attested  by 
microscopic  examination  of  the  blood.  The  fifteen  infants  which 
were  treated  therapeutically  with  cioccolattini  only  suffered  a 
single  attack  in  each  case. 

Examination  of  the  spleen  after  the  termination  of  the 
sanitary  work  showed  enlargement  in  I4'48^,  while  at  the 
commencement  of  January  it  amounted  to  2"67^. 

During  the  whole  summer  two  children  died  of  malignant 
fever,  according  to  the  diagnosis  of  the  local  doctors,  which, 
however,  was  conducted  without  a  microscopical  examination 
of  the  blood. 

The  quantity  of  quinine  expended  in  these  three  sanitary 
campaigns  at  Marathon  amounted  to  an  average  of  I5"6 
grammes  for  each  inhabitant  in  1907,  32'3  grammes  in  1908, 
and  5 '6  grammes  in  1909. 

The  total  expense  ^  during  1907  reached  Drachmas  ( =  Francs) 
5,715 — or   an    average   of   Drs.    370    for    each    patient   under- 
going the  preventive  treatment.     In  1908  the  amount  expended 
reached  Drs.  6,736 — or  Drs.  5"i5  per  head;  whilst  in  the  year 
^  Including  pay  of  the  medical  men. 


448  ANTI-MALARIA   MEASURES   IN   GREECE  [Sect. 

1909  Drs.  2,226  were  spent,  or  an  equivalent  of  Drs.  1*69  for 
each  of  the  inhabitants.  It  consequently  appears  that  the 
Italian  system  is  more  expensive  than  the  other  methods. 

We  gather  the  following  conclusions  from  our  three  years' 
work  at  Marathon.  The  Koch  preventive  method  seems  likely 
to  meet  with  considerable  difficulties  in  our  country ;  that  of 
Celli,  in  combination  with  the  destruction  of  the  larvae  of  the 
Anopheles^  gives  excellent  results,  and  is  an  ideal  method  of 
combatting  malaria.  Nevertheless,  that  method  is  not  easily 
applicable  in  every  part  of  the  country,  as  it  requires  continual 
superintendence  of  an  expert  in  order  to  oblige  the  inhabitants 
to  continue  taking  quinine  every  day  during  the  whole  summer, 
and  for  a  series  of  years,  until  a  permanent  cure  is  effected.  It 
can,  however,  be  employed  with  excellent  results  in  the  army 
and  the  navy,  in  the  prisons,  railway  and  other  companies,  in 
mines,  in  villages  forming  private  property,  and,  generally  speak- 
ing, everywhere  where  there  is  a  single  authority,  with  the 
power  of  enforcing  that  method  willy-nilly  upon  those  under 
it.  Throughout  the  rest  of  the  country,  however,  which  is  in- 
habited by  independent  people,  who  regulate  at  will  their  life 
and  diet,  it  is  difficult  for  the  Italian  method  to  be  introduced. 
Those,  however,  who  have  suffered  from  fever  and  have  taken 
quinine  at  irregular  intervals  without  being  able  to  throw  off 
the  disease,  will  be  gladly  surprised  to  see  the  favourable  results 
which  are  produced  by  the  methodical  use  of  quinine  such  as 
applied  by  us  at  Marathon  during  the  third  year  of  our  work  : 
and  so  recovering  their  shaken  faith  in  the  drug,  they  will  most 
probably  end  by  adopting  the  Italian  preventive  method. 


V 

Sanitary  work  at  Laurium. — A  work  of  a  similar  nature 
was  undertaken  during  the  summer  of  1909  by  the  Greek 
Laurium  Mines  Company,  the  employees  of  which  suffer  ex- 
cessively every  summer  and  autumn  from  malaria.     This  work 


so]  LAURIUM   AND   ATHENS  449 

was  confined  to  the  preventive  treatment  with  quinine,  as  in 
excavating  the  mines  numerous  large  hollows  are  formed  in 
the  soil,  and  these  being  filled  with  water  and  serving  as 
nurseries  of  Anopheles,  it  becomes  impossible,  owing  to  their 
large  extent,  to  destroy  the  larvae.  Every  miner  was  provided 
with  two  tablets  (o'40  gramme)  of  State  quinine  per  diem  from 
the  commencement  of  May  to  the  end  of  October.  The  result 
of  this  treatment  was  that  out  of  480  miners  only  28  (5"8%) 
were  attacked  by  malaria,  whereas  in  each  of  the  foregoing 
years,  1 906-1 908,  from  30  to  40%  suffered  from  fevers.  That 
this  good  result  is  due  to  the  use  of  quinine  may  be  seen 
from  the  fact  that,  of  75  miners  who  failed  to  take  quinine 
regularly,  34  were  attacked  by  malaria. 

VI 

Sanitary  work  in  Athens. — In  the  city  of  Athens  the  two 
suburbs  which  suffer  most  severely  from  malaria  are  those 
of  Pankrati  and  Batraconesi,  where,  before  the  year  1900  the 
percentage  of  cases  fluctuated  between  25  and  30%,  and  from 
1901-1906  it  reached  49%,  and  even  as  high  as  92%,  as  will 
be  seen  in  the  following  table.  This  excessive  prevalence  of 
malaria  was  due  to  the  small  pools  in  the  bed  of  the  river 
Ilissos,  which  were  found  to  be  full  of  larvae  of  Anopheles 
superpictus. 

As  a  means  of  coping  with  this  situation,  the  League  re- 
quested the  Government  to  undertake  certain  sanitary  works 
in  the  bed  of  the  Ilissos,  and,  as  a  matter  of  fact,  in  the 
summer  of  1906  the  Government  carried  out  the  work  in 
question,  which  consisted  chiefly  in  levelling  the  inequalities 
in  the  river-bed,  and  in  drawing  off  the  water  by  means  of 
a  narrow  channel  where  the  development  of  Anopheles  was 
hindered  by  the  rapid  flow  of  the  water.  In  1906  the  work 
was  but  slowly  conducted,  and  consequently  the  influence  upon 
malaria  was  slight,  as  shown  by  the  table  given  below.     During 

2  F 


45° 


ANTI-MALARIA   MEASURES    IN   GREECE         [Sect.  50 


the  second  year,  1907,  the  percentage  of  cases  of  malaria  in 
the  Pankrati  fell  to  2  or  3%,  and  in  the  Batraconesi,  where 
the  work  was  carried  out  later  in  the  season,  it  fluctuated 
between  25  and  30%.  In  the  summer  of  1908  the  work  of 
sanitation  commenced  at  the  proper  time  in  the  Ilissos,  and 
as  a  result  the  number  of  cases  of  malaria  fell  to  1%.  In 
1909  the  work  was  also  carried  out  in  due  time  and  the  cases 
fell  to  o-66%.  It  is  to  be  remarked  that  no  preventive  use  of 
quinine  was  resorted  to,  and  so  the  satisfactory  results  are 
entirely  due  to  the  work  carried  out  in  the  bed  of  the  Ilissos. 

Comparative  Table  of  the  Cases  of  Malaria  among  the 
Children  in  the  Pankrati  and  Batraconesi  Suburbs 

Before  the  adoption  of  the  sanitary  measures  {Pezopoulos  and  Cardamatis) 

Percentage 
In  the  summer  of  1901  out  of     280  children  260  were  attacked    .         92*85 
„     „         „  „  1902    „    „       200         „        160      „  „  .         8o-oo 

„  1903    »    »       235         „        192      „  „  .         8170 

„  1904    „    „       180        „  89      „  „  .         49-09 

„   1905     „    „       200         „        185      „  „  .         92-50 


?)     It 


During  the  five  years 


1,095 


886 


80-90 


After  the  adoption  of  the  sanitary  measures  {Cardatnatis) 

In  the  summer  of  1906  out  of  301  children  177  were  attacked, 

„     „        „         )5  1907    ?)    „  345         ')  73      )'  J5 

„     „        „         »  1908    „    „  300        „  8      „  „ 

„     ,,        »         »  1909    »    ,>  300        „  2      „  „ 


Percentage 

58-80 

21-15 

2-66 

0-66 


BANKS   OF   THE    ILISSOS,    ATHENS,    UNTRAINED.       BY    DR   CARUAMATIS. 


KANKS    OF    THE    II.LSSOS,    TRAINED.       KV    DR    CARDA.MATIS. 

[  To  face  page  450, 


By  Dr  Professor  CLAUS  SCHILLING 

Late  Medical  Officer  of  the  German  Colonial  Office,  at  Togo,  West  Africa 
Abteilungsleiter  im  Institute  fur  Infektionskrankheiten,  Berlin. 

51.  The  Prevention  of  Malaria  in  German  Possessions.— 

When  Germany  began  colonising,  she  found  herself  face  to  face 
with  the  problem  of  developing  the  raw  material  of  the  territories 
she  had  occupied,  making  it  accessible  to  trade  and  civilisation. 
The  development  arrived  at  in  these  twenty-six  years  has  not 
been  such  as  to  render  the  colonies  able  to  dispense  with  the 
support  of  the  mother-country.  The  empire  has  also  to  make 
it  her  care  to  improve  the  health  conditions  of  those  under  her 
protection.  But  the  science  of  Hygiene  is  able  to  obtain  only 
by  slow  degrees  the  place  due  to  it  in  the  work  of  colonisation, 
conducted  on  economical  principles.  It  requires  the  greatest 
energy  on  the  part  of  the  doctors  to  obtain  what  is  necessary 
from  the  very  slender  means  at  the  disposal  of  the  authorities. 
Of  the  tropical  colonies  of  Germany — viz. :  East  Africa, 
Kamerun,  Togo,  and  the  north  of  South-west  Africa,  New 
Guinea,  the  Carolines,  and  Samoa  in  the  South  Seas — only  the 
two  last-named  are  free  from  malaria ;  in  all  the  others  it  is, 
next  to  small-pox,  the  most  widespread  of  diseases.  The 
following  summary  gives  information  as  to  the  frequency  of 
malaria  amongst  the  natives. 

451 


452  PREVENTION  IN   GERMAN  POSSESSIONS  [Sect. 

TABLE    I. 


Age 

IN  Years. 

Up  to 

Up  to 

Up  to 

Up  to 

Up  to 

Up  to 

Up  to 

I. 

2. 

5- 

10. 

15- 

20. 

SO. 

New  Guinea : 

Bogadjim  (Koch) . 

80 1 

41 '6 

0 

Bongo  (Koch) 

100 

46-1 

23-5 

0 

0 

Gazelle     peninsula     (Demp- 

1 

wolff)         .... 

19 

32 

22 

I 

8 

12 

East  Africa  : 

Tanga  (Panse) 

48 

88 

79 

45 

i5'3 

Dar  -  es  -  Salaam  :     Indians 

(OUwig)    .... 

29-6 

32-5 

29-3 

i6-i 

Dar  -  es  -  Salaam  :     Negroes 

(Ollwig)    .... 

390 

40-8 

20'I 

7-6 

Kamerun  :  Duala  (Plehn)     . 

94 

92 

85 

5° 

Togo  :  Anecho  (Schilling)     . 

88-8 

71-5 

74-0   1    68-0 

16 -6 

1  The  percentage  of  those  examined  found  to  contain  parasites. 

It  is  evident  from  this  table,  amongst  other  things,  that  the 
development  of  immunity  in  malarial  districts  is  by  no  means 
of  equal  extent.  It  is  evidently  connected  with  the  frequency 
of  infection  by  stings  from  infected  Anophelines.  In  spots 
where  no  decided  alternation  between  the  rainy  and  the  dry 
season  takes  place  {e.g.,  New  Guinea)  there  is  also  constant 
opportunity  for  fresh  infection  and  for  re-infection.  This  point 
is  to  be  taken  into  consideration  in  a  plan  of  malaria  prophy- 
laxis. The  table  is  so  far  of  interest  as  showing  that  active 
immunity  in  malaria  by  no  means  sets  in  with  certainty  {e.g., 
in  Duala,  only  in  50%  of  the  natives  who  had  been  exposed 
at  least  for  ten  years  to  the  infection  without  a  break).  The 
chances,  therefore,  of  acquiring  active  immunity  fluctuate 
between  13:1  and  i:i  during  a  sojourn  of  from  ten  to  fifteen 
years  in  dangerous  malarial  districts.  The  practical  unimport- 
ance of  the  objection,  that  malaria  prophylaxis  interrupts  this 
active  immunity,  may  be  considered  as  proved  by  this  com- 
putation, 


SI 


MALARIA   INDEX   IN   TANGA 


453 


Diagrarils  1  and  2  show  a  comparison  of  the  value  of  micro- 
scopic examination  of  the  blood  and  palpation  of  the  spleen. 
They  show  that  in   Tanga,  East  Africa,  the  two  curves  of 


Diagram  i. 


Malaria  index  in  Tanga  (Panse). 


Number  of  those  examined, 

—  —  Parasites  found. 

-  -  -  -  Spleen  enlarged. 


the  spleen  rate  and  the  positive  results  of  blood  examination 
correspond  approximately,  so  that  the  latter  could  replace  the 
former.     But  in  Anecho  it  was  only  in  children  between  two 


454 


PREVENTION  IN  GERMAN  POSSESSIONS 


[Sect. 


and  five  years'  old,  that  palpation  of  the  spleen  produced 
higher  results  than  examination  of  the  blood ;  whereas  in 
later  years  the  spleen  tumour  quickly  subsides,  even  where 
malarial  infection  exists.  So  that  if  the  spleen  tumour  is  to 
be  made  use  of  as  an  indicator  of  the  malarial  index  of  some 
special  locality,  the  relation  between  spleen  tumour  and  condi- 


50  years. 


Malaria  index  in  Anecho  (Schilling). 

Number  of  those  examined. 

Parasites  found. 

Spleen  enlarged. 


tion  of  the  blood  must  be  first  of  all  ascertained  by  comparative 
examination,  which  must  then  be  taken  into  consideration  in 
the  computation. 

To  introduce  individual  therapeutics  only  on  the  basis  of 
spleen  palpation  is  not  feasible,  according  to  Patise's  and  my 
own  examinations.  Pause,  for  instance,  found  that  in  a  positive 
condition  of  the  blood  the  spleen  tumour  was  absent, 


5i]  PRELIMINARY   MEASUREMENT  455 

7  children  under    2  years,  in  14%  of  those  examined. 
52        „  „         5         „       28 

31        »  ..       10        »        51 

5        ..  ,,15         n        80 

Without  examination  of  the  blood,  all  these  persons  would 
have  been  deprived  of  quinine  therapeutics. 

As  regards  the  frequency  of  differetit  forms  of  malaria,  the 
following  table  for  Dar-es-Salaam,  1908- 1909,  gives  information. 


TABLE 

II. 

There  were  found 

"  Rings." 

1    Tertians. 

Quartans. 

Crescents. 

In  April- June  1908 

.      1,039 

28 

122 

121 

In  July-Sept.       „ 

.          .     1,184 

50 

115 

173 

In  Oct.-Dec.         „ 

.          .        567 

13 

87 

132 

In  Jan. -March  1909 

•       594 

40 

138 

165 

In  reference  to  mortality  amongst  children^  in  consequence 
of  malaria,  Steuber  states  that  before  the  introduction  of  pro- 
phylaxis in  places  on  the  coast,  of  the  total  number  of  deaths 
amongst  children  under  four  years,  44%  in  Dar-es-Salaam, 
57%  in  Lindi,  and  25%  in  the  higher  situated  Tabora,  were 
due  to  malaria. 

On  the  introduction  of  malaria  prophylaxis  into  German 
colonies,  the  principle  was  laid  down  that  it  should  always  be 
preceded  by  a  statement  of  the  so-called  endemic  index  ;  that 
is  to  say,  by  ascertaining  what  percentage  of  the  inhabitants  of 
one  place  were  infected  by  malaria  at  the  time.  The  researches, 
whenever  possible,  were  extended  over  various  quarters  of  the 
town,  in  order  to  discover  what  parts  were  seriously  threatened. 
In  doing  this,  it  turned  out,  moreover,  that  not  all  parts  of 
the  population  were  equally  attacked  by  the  disease,  or  were 
equally  predisposed  to  it.  (See  Tables — Indians  and  Negroes  in 
Dar-es-Salaam.)  Further,  it  is  essential  that  the  examinations 
of  the  population  be  repeated  at  different  seasons  of  the  year. 

^  By  this  are  meant  the  ring  forms  of  all  three  kinds  of  parasites,  which  could  not 
be  distinguished  one  from  the  other,  and  were  not  accompanied  by  the  characteristic 
forms  of  division,  or  by  gametes. 


456  PREVENTION  IN  GERMAN  POSSESSIONS  [Sect. 

It  is  specially  important  with  children  of  a  year  old,  whether 
they  have  already  gone  through  a  rainy,  i.e.,  a  malarial  period, 
or  not. 

In  the  German  colonies  the  first  place  is  given  to  fighting 
malaria  with  quinine.  In  Stephansort,  in  New  Guinea,  Robert 
Koch  for  the  first  time  adduced  positive  proof  that  in  a  perfect 
hot-bed  of  malaria  it  is  possible  to  reduce  this  disease  to  a 
minimum,  nay,  make  it  disappear  altogether,  and  this  by  the 
exclusive  aid  of  quinine. 

Thus,  on  the  island  of  Brione  (Istria),  Frosch,  under  Koch's 
superintendence,  carried  on  a  struggle  against  malaria  in  the 
years  1901  -  1902.  At  the  beginning  of  the  campaign  in 
December  1900  there  were  63  =  48%  of  the  inhabitants  infected 
with  malaria.  In  the  first  nine  months  of  the  struggle,  22  cases 
in  all  occurred  amongst  labourers,  drawn  from  regions  free  from 
fever ;  from  that  time,  in  the  next  fourteen  months,  there  were 
no  fresh  cases  of  infection  at  all,  and  only  nine  relapses  !  ^ 

The  fight  against  malaria  is  therefore  twofold,  consisting, 
(i)  in  the  treatment  of  the  sick,  and  (2)  in  the  destruction  of 
the  parasites  that  have  already  made  their  way  into  the  human 
organism — the  "prophylaxis"  proper.  If  the  solution  of  these 
problems  can  be  brought  about,  malaria  must  disappear. 

Individual  prophylaxis  can  be  practised  according  to  an 
empirical  scheme  which  has  proved  useful ;  thus  I  have  found 
that  in  the  worst  fever  regions,  on  marches  and  expeditions, 
the  dose  of  one  gramme  of  quinine  every  fifth  and  sixth  day  is 
sufficient  to  guard  against  fever.  Other  authors  recommend 
other  methods  ;  as  to  the  value  of  the  separate  schemes,  the 
last  word  has  not  been  said.  But  it  is  certain  that  individual 
quinine  prophylaxis  is  able  to  prevent  the  outbreak  of  malaria 
infection,  and,  on  the  other  hand,  that  the  use  of  the  drug  may 
be  left  to  the  patient  himself,  under  the  control  of  the  doctor. 
It  is  a  different  thing  with  the  general  part  of  the  fight,  with 

^  This  work  does  not  belong  to  my  present  subject.     I  mention  it  here  because  it 
prepared  for  and  completed  the  experiment  of  Stephansort. 


5i]  STEPHANSORT  457 

the  treatment  of  the  persons  infected  :  the  latter  can  only  be 
detected  by  the  doctor  or  by  a  staff  specially  trained  for  the 
purpose,  and  their  treatment  must  be  individualised.  The  fight 
against  malaria  by  this  method  can  therefore  only  be  begun 
and  carried  out  under  medical  supervision. 

In  the  year  1900  Koch  found  about  734  persons  in 
Stephansort,  New  Guinea,  157  of  whom  harboured  malaria 
parasites ;  240  Chinese  with  63  infected,  209  Malayans  with 
53  infected,  and  264  Milanesians  with  157  infected  were 
examined.  In  the  beginning  the  infected  persons  were  treated 
with  one  gramme  of  quinine,  until  the  parasites  had  disappeared 
from  the  blood  ;  from  that  date,  for  two  months,  every  eighth 
and  ninth  day  one  gramme  of  quinine  each  was  given.  The 
result  was  a  striking  one,  as  appears  from  the  number  of 
patients  admitted  to  the  hospital. 


January  . 

February 

March    . 

April 

May 

June 


24  admitted  on  account  of  malaria. 

13 
2 
3 
I 


Koch  emphasises  that  the  months  of  January  to  May  are 
notorious  as  being  specially  dangerous,  and  that  also  in  the 
year  1900  the  rainy  season  lasted  right  on  into  June.  Never- 
theless they  succeeded  in  reducing  malaria  morbidity  to  a  very 
slight  amount,  more  especially  as  the  cases  of  illness  from  it 
which  had  occurred  from  April  to  June  were  only  relapses  and 
not  fresh  cases  of  infection.  And  this  success  was  obtained 
through  the  rational  usage  of  quinine.  It  does  not  make  any 
difference  to  the  importance  of  this  proof,  even  if  one  admits 
that  the  conditions  were  rather  favourable  in  Stephansort — 
being  here  the  case  of  plantation  labourers  living  far  from  their 
own  homes  and  under  complete  control — and  that  the  success 
was  lost  with  the  time  as  the  control  slackened.  The  proof 
I  mentioned  was  given,  and  nothing  more  has  been  intended. 


458  PREVENTION  IN  GERMAN  POSSESSIONS  [Sect. 

It  was  only  natural  that  Koch's  experiments  in  Stephansort 
were  copied  in  the  other  German  colonies  and  adapted  to  local 
conditions. 

In  German  South-west  Africa,  the  northern  tropical  districts 
of  which  suffer  badly  from  malaria,  Vagedes  has  undertaken 
to  make  practical  use  of  Koch's  ideas  ;  because  for  those  districts, 
where  numerous  small  collections  of  water  such  as  those  which 
occur  in  footprints  of  cattle,  horses  and  wild  animals,  serve  as 
breeding-places  for  Anophelines,  and  where  mosquito  preven- 
tion by  means  of  wire-gauze,  screening  the  native  huts,  cannot 
be  spoken  of,  quinine  treatment  and  prophylaxis  are  the  only 
possible  methods.  In  Franzfontein  and  the  surrounding  settle- 
ments, Vagedes  found  30%  to  75^  of  the  inhabitants  infected 
with  malaria.  Every  eighth  and  ninth  day,  ninth  and  tenth 
day,  and  every  ninth,  tenth  and  eleventh  day  respectively 
the  infected  adults  were  given  one  gramme  at  a  time ;  the 
children  correspondingly  less.  Certainly,  it  was  not  un- 
important that  quinine  was  given  whenever  possible  in  the 
form  of  hydrochloride  in  solution,  and  only  in  rare  cases 
in  wafers.  In  children,  who  easily  rejected  the  solution,  sub- 
cutaneous administration  was  adopted.  This  treatment  was 
continued  from  two  to  three  months.  The  results  were  very 
satisfactory.  In  Franzfontein,  with  its  fixed  and  therefore 
regularly-treated  population,  the  percentage  of  infected  persons 
decreased  from  79^  to  9^ ;  out  of  165  persons  only  7  new 
infections  and  4  recidives  occurred.  In  Tumamas  ^7%  ^^id 
in  Canas  30^  of  infected  persons  were  found  at  the  beginning 
of  the  campaign.  In  the  course  of  the  following  rainy  season 
the  settlements  were  free  from  malaria. 

Koch's  ideas  of  anti  -  malarial  measures  have  been  also 
applied  to  Dar-es-Salaam. 

Dar-es-Salaam,  at  the  time  when  Ollwig  began  his  activities 
as  director  of  the  anti-malarial  brigade,  was  a  town  of  12,000 
to  15,000  inhabitants.  The  population  consisted  of  Europeans 
(officials   and    officers  stationed    there    for  periods  of  one  and 


5l]  DAR-ES-SALAAM  459 

a  half  years,  and  merchants  with  engagements  of  longer 
periods),  Indians,  Goanese,  Arabs  and  Negroes.  The  Europeans 
live  partly  on  the  peninsula  facing  north  -  east,  and  partly 
in  the  districts  near  the  harbour.  The  Indians  live  in  the 
adjacent  blocks  of  houses  situated  more  inland,  and  the  native 
town  is  grouped  around  these.  The  larger  portion  of  the 
town  is  surrounded  by  a  depression  where  water  remains  for 
long  periods  through  the  dry  season,  and  which  renders  the 
cultivation  of  rice  possible.  Along  the  shore  wells  spring  up 
and  form  ditches  and  ponds.  The  town  is  therefore  surrounded 
by  a  ring  of  water  -  collections  which  offer  most  favourable 
breeding-places  to  Anophelines. 

The  abolition  of  these  water-collections,  the  land-level  being 
but  little  higher  than  the  sea-level  at  high  tide,  would  have 
involved  very  great  technical  difficulty,  and  consequently  would 
have  been  most  expensive.  Other  measures,  such  as  oiling 
of  single  water-collections  with  petrol,  did  not — as  was  to  be 
expected  —  affect  the  number  of  Anophelines  infecting  the 
houses. 

Ollwig  first  tried  to  establish  the  malaria  index  based  on 
microscopic  examination  of  the  blood.  Palpation  of  the  spleen 
does  not  appear  to  have  been  practised.  Ollwig  accepts  as  a 
sign  of  malarial  infections  also  the  basophile  granulation  of 
the  red  blood  corpuscles,  if  he  could  find  no  other  cause 
(anaemia  due  to  ankylostomiasis)  for  its  appearance.^ 

For  this  purpose  the  town  was  divided  into  twenty  blocks, 
and  the  inhabitants  of  these  quarters  were  regularly  examined 
without  exceptions.  Owing  to  the  fixedness  of  the  Indian  and 
Goanese  population,  this  examination  could  be  fairly  well 
carried  out;  in  the  Negro  quarters,  however,  this  was  an 
extremely  difficult  task,  as  they  continually  change  their 
domiciles  from  village  to  town  and  vice  versa.  Therefore  in 
the  following  table  the  Negroes  mentioned  have  undergone  a 
single  examination. 

1  Due  to  other  causes. — R.  Ross. 


46o 


PREVENTION  IN  GERMAN  POSSESSIONS 


[Sect. 


From  the  table,  in  the  column  devoted  to  "  first  examina- 
tions," the  malaria  index  is  given  fairly  accurately,  and  shows 
that  spontaneous  immunisation  in  adults  does  not  occur  to 
any  appreciable  extent,  and  that  therefore  the  treatment  with 
quinine  was  justified  also  in  the  case  of  adults. 


TABLE    III 


Children 

Children 

Children 

A^..U, 

First 

up  to  I  year 

from  I  to  5  years 

over  5  years 

examined     infected 

examined 

infected 

examined 

infected 

examined 

infected 

Indians 

examinations 

27 

8=29% 

62 

20  =  32% 

l8l 

53  =  29% 

650 

105  =  16% 

and        1 

Goanese 

Later 

examinations 

75 

2=27% 

211 

28  =  13% 

415 

23=5-5% 

1,702 

82=4'8% 

First 

examinations 

26 

9  =  34% 

94 

45  =  47% 

288 

74=26% 

3.338 

238=7-6% 

Negroes    < 

Later 

exammations 

42 

8  =  19% 

169 

55=33% 

627 

99  =  15% 

" 

1 

The  "  first  examinations  "  were  made  in  August,  September 
and  November  1901,  and  January  to  March  1902  ;  the  "later 
examinations"  from  March  1902  to  March  1903 — therefore 
after  i"5  year's  campaign  at  most. 

On  the  contrary,  compared  to  Dar-es-Salaam  the  malaria 
index  of  some  villages  further  inland  appeared  rather  high  :  of 
children  up  to  one  year  of  age,  77*5%  were  infected  ;  of  children 
up  to  five  years  of  age,  57'3% ;  of  children  above  five  years  of 
age,  3 1 '9%;  of  adults,  217%. 

The  anti-malarial  measures  were  limited  to  quinine  treat- 
ment of  all  persons  who  were  found  infected,  as  well  as  those, 
naturally,  who  put  themselves  at  the  disposal  of  the  doctor. 

OUwig  gave  adults,  at  first  on  three  consecutive  days  and 
later  on  every  fifth  and  sixth  day,  one  gramme  quinine  muriate  ; 
after  nine  days'  interval  again  three  quinine  days,  and  so  on 
for  two  and  a  half  to  three  months.  Children  were  given  a 
corresponding  quantity  of  the  drug  in  solution  and  a  lump  of 


5i]  DAR-ES-SALAAM  461 

sugar  afterwards  ;  adults,  mostly  in  form  of  tablets.  One  can 
see  it  was  a  question  of  a  purely  therapeutic  anti-measure, 
and  not  one  of  prophylaxis. 

Many  of  the  details  in  Ollwig's  interesting  report  (one  and 
three-quarter  years  after  the  anti-work)  cannot  be  referred  to 
here,  and  only  the  "facit"  is  drawn  as  resulting  from  Table  III. 
In  one  school  (not  referred  to  in  the  table)  they  were 
successful  in  reducing  the  number  of  infected  persons  from 
21*0%  (August  1901)  to  3-5%  (March  1903).  Amongst  the 
Indian  population  from  July  1901  to  June  1902,  410  cases, 
from  July  1902  to  May  1903,  210  cases  of  malaria,  came  to 
the  knowledge  of  the  medical  officer.  It  may  be  noted  here 
that  the  Indians  gradually  gained  confidence  with  the  medical 
officer ;  and  so  in  the  first  half  of  the  period  more  infections 
remained  unobserved  than  in  the  second  half.  In  the  Negro 
children,  on  the  contrary,  the  results,  though  noticeable,  were 
not  so  favourable  (decrease  from  34%  to  19%).  This  can 
easily  be  understood  because  the  Negro  population  is  subject 
to  constant  fluctuations,  and  it  is  only  seldom  possible  to 
continue  the  after-treatment  long  enough. 

Statistics  of  adult  Negroes  have  been  omitted  from  Ollwig's 
report ;  the  7'^%  of  infected  adults  are  of  little  importance  in 
proportion  to  the  26-40%  of  the  children. 

Ollwig  proves  in  his  report  that  the  reduction  in  the  malarial 
morbidity  can  have  been  caused  neither  through  climatic  factors 
nor  through  other  possibly  adopted  measures.  The  periods  of 
rain  and  the  numbers  of  Anophelines  were  not  less  during  the 
time  of  the  observation  than  previously,  and  the  work  of 
assainment  and  petrolisation  of  the  water-collections  have  been 
practised  so  irregularly  and  to  such  a  slight  degree  that  these 
measures  cannot  have  had  great  influence  upon  the  large  differ- 
ences in  the  numerical  value. 

Ollwig  rightly  emphasises  that  only  a  very  small  staff — 
one  medical  officer,  one  nurse,  one  European  and  five  coloured 
assistants — has  been  necessary  for  this  successful  struggle. 


462  PREVENTION  IN  GERMAN  POSSESSIONS  [Sect. 

It  is  to  be  regretted  that  Oil  wig  did  not  calculate  the  total 
cost,  as  this  calculation  would  have  shown  how  cheap  this 
method  of  anti- malarial  measures  is  in  comparison  to  other 
methods.  Up  to  1908  the  number  of  native  assistants  never 
exceeded  half  a  dozen,  besides  three  to  four  Europeans,  by 
whom  15,627  natives  were  examined  microscopically  and  treated 
with  quinine. 

Subsequently  anti-malarial  work  was  continued  in  Dar-es- 
Salaam.  For  this  work  only  one  medical  officer  was  available, 
whose  time  was  greatly  occupied  with  quarantine  and  other 
administrative  work ;  the  staff  of  assistants  was  not  much  aug- 
mented either.  Ross-Ruge's  method  of  blood  examination  (the 
so-called  thick  film  method)  was  adopted,  and  this  method 
made  it  possible  to  discover  even  quite  isolated  parasites.  The 
consequence  was  a  remarkable  increase  in  the  positive  cases 
since  October  1907,  and  for  this  reason  the  numerical  values 
given  in  Table  V,  before  and  after  that  date,  are  not  to  be 
compared  with  each  other  "  without  further  consideration." 

Other  methods  of  anti  -  malarial  measures  could  not  be 
practised  except  to  a  very  slight  degree,  as  the  money  provided 
by  the  Government  was  just  enough  for  quininisation.  In 
some  houses  mosquito-proof  rooms — such  as  verandas — have 
been  arranged  ;  the  petrolisation  of  water  -  collections  could 
naturally  yield  but  little  success. 

In  Tanga,  the  most  important  seaport  next  to  Dar-es-Salaam, 
the  anti-malarial  work,  according  to  the  example  of  the  capital, 
was  not  taken  up  until  1905  (Table  IV).  Besides  one  medical 
officer  only  three  to  four  nurses  understanding  microscopical 
examination  of  the  preparations  were  available.  In  addition 
to  microscopical  findings,  tumours  of  the  spleen  decided  the 
need  of  treatment.  This  treatment  was  commenced  with  one 
gramme  doses  in  adults,  and  correspondingly  lower  doses  in 
children,  on  two  consecutive  days  per  week,  and  was  continued 
for  three  months.  In  all  cases  an  enormous  decrease  of  splenic 
tumours   (from    1,040   to    1,042)  and    distinct   improvement   in 


51] 


TANGA 


463 


the   general    condition    have  been  stated.     Only   in  very  rare 
cases  this  cure  did  not  sufifice  to  cause  the  parasites  to  disappear. 


TABLE   IV 


1905-06  i 

All    persons  with 
tumour    of  the 
spleen  or  mal. 
parasites         in 
blood,         were 
treated        with 
quinine     for    3 
months. 

Negroes 

Indians 

Children 

Adults. 

Children 

Adults. 

June-Aug. 
(before  quinine  treatment) 

49  "6% 

12  "4% 

54'o% 

13-8% 

Jan.-March 
(after  quinine  treatment) 

24-6% 

5-3% 

29-5% 

3  "9% 

1906-07  A 

In  June,  July,  and 
Aug.  all  nations 
became  quinine 
prophylactically 

May-July 

84-0% 

14-9% 

87-1% 

i8-3% 

Dec. -March 

30-0% 

6-1% 

3i'3% 

4-6% 

1907-08 

1907 
April-June 

i8-3% 

12-6% 

July-Sept. 

i6-i% 

9-5% 

Oct. -Dec. 

i4"o% 

7-5% 

1908 
Jan.-March 

I2'0% 

6-8% 

1908-09 

As  the  year  before 

April-June 

668 

170=24% 

2,025 

295  =  14% 

July-Sept. 

755 

181  =  24% 

1,879 

272=18% 

Oct.-Dec. 

601 

121=20% 

2,100 

258=14% 

1909 
Jan.-March 

846 

208=24% 

2,23s 

532=23% 

1 

The  population  in  Tanga  being  smaller  and  much  more  fixed 
than  in  Dar-es-Salaam,  the  result  during  the  first  year  was 
more  satisfactory.  From  March  to  June  1906,  however,  the 
number  of  infections  increased  threefold,  which  is  explained 
by  the  extraordinary  amount  of  rain  during  that  time.  In  the 
course  of  the  following  dry  season  the  index  sunk  to  the  level 


464  PREVENTION  IN  GERMAN  POSSESSIONS  [Sect. 

of  the  previous  year.  In  1907  to  1909,  apparently  another 
rise  in  the  cases  of  malarial  infection  occurred  in  Europeans 
at  Tanga  ;  but  this  is  due  to  numerous  immigrations  from  further 
inland,  the  people  in  case  of  infection  having  the  opportunity 
to  get  to  the  hospital  in  Tanga  by  means  of  the  recent  rail- 
way extension.  Among  the  settled  white  inhabitants  of  the 
city  of  Tanga  the  malaria  morbidity  has  gone  back  from  37% 
to  35y/  of  the  total  strength. 

Drainage  of  the  town,  petrolisation  —  though  not  quite 
general  —  of  water-collections,  and  deforestation  of  numerous 
uncultivated  pieces  of  land,  were  undertaken  simultaneously ; 
also  many  Europeans'  houses  were  provided  with  wire  -  gauze 
protection. 

The  increase  of  malaria  during  1908  to  1909  {vide  Table  V) 
may  be  due  to  the  hospital  being  more  generally  used  by  the 
patients  from  the  district,  which  is  more  and  more  frequented 
by  Europeans,  and  by  people  employed  in  the  construction 
of  the  railway.  In  Dar-es-Salaam  itself  malaria  has  diminished 
to  such  a  degree  among  the  whites  settled  there  in  the  European 
quarter,  that  individual  quinine-prophylaxis  is  no  longer  regarded 
absolutely  necessary ;  rather,  numerous  officials  have  passed 
the  whole  of  their  one  and  a  half  years'  time  of  service  without 
taking  quinine,  and  without  once  contracting  malaria.  Many, 
however,  continue  the  quinine  prophylaxis. 

In  the  other  settlements  in  East  Africa,  where  medical 
officers  and  officials  are  stationed,  no  proper  anti-malaria  work 
is  practised  to  any  appreciable  degree. 

From  a  general  report  on  infected  Europeans  who  have 
been  treated  by  the  medical  officers,  it  can  be  concluded  that, 
both  together,  the  anti  -  malarial  measures  and  the  individual 
prophylaxis  in  Dar-es-Salaam  as  well  as  in  Tanga  have  been 
a  success, 


51] 


RESULTS 
TABLE   V 


46s 


Europeans  in  Dar-es-Salaam. 


Strength,  Dar  -  es  -  Salaam 
(town),  (Iststarke) 

Morbidity,  malaria  and 
blackwater  fever  in  the 
district  of  Dar-es-Salaam 

Mortality,  malaria  and  black- 
water    ..... 


1902-03. 

1903-04. 

1904-05, 

1905-06. 

1906-07. 

1907-08. 

3" 

377 

380 

657 

851 

897 

^  166 

168 

141 

355 

287 

268 

I  S3 -3% 

44  "5% 

37'i% 

54-0% 

337% 

29-8% 

7 

0 

3 

4 

6 

6 

1908-09. 


743 

342 

46  '0%  • 


Europeans  in  Tanga. 


Strength,       Tanga 
(Iststarke)     . 


(town), 


Morbidity,  malaria  and  black- 
water  fever,  in  the  district  of 
Tanga  ..... 

Mortality,  malaria  and  black- 
water    ..... 


95 

148 

192 

205 

211 

222 

c  no 

61 

178 

156 

128 

206 

^"5-8% 

41-2% 

87-5% 

76-1% 

6o-6% 

92-8% 

2 

2 

5 

6 

3 

2 

258 
203 

787% 


1   Vide  page  464. 


The  reports  on  the  garrison  (Table  V«)  were  the  most  accurate 
ones,  as  the  majority  of  recorded  infections  were  observed  by  a 
medical  officer.  The  statements  about  "  civil  persons  "  (Table  Nb) 
are  far  less  precise,  only  a  small  number  of  the  malaria  infections 
among  them  coming  to  the  knowledge  of  the  doctor.  The 
figures  showing  the  morbidity  here  have  therefore  been  stated 
far  too  low,  but,  as  these  conditions  do  not  change  from  year 
to  year,  it  is  quite  permissible  to  compare  the  different  years 
with  each  other. 

With  the  coloured  population  matters  are  entirely  different 
(Table  VI).  The  percentage  value  in  itself  is  here  not 
standardised,  as  it  was  impossible  at  the  repeated  examina- 
tions to  find  always  the  same  persons  who  had  been  treated 
with  quinine.  In  addition  to  those  there  were  persons  who 
had  come  into  town  meanwhile,  and  who  had  been  treated 
with   quinine   only   insufficiently   or   not   at   all.     Some   other 

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Sect.  51 J 


RESULTS 


467 


comparative  instances  must  be  sought,  and  they  are  given  in 
the   blood   examination   of  the    inhabitants   of  the  suburbs   of 


TABLE   V^ 


View 

ON   THE  MALARIA   MORBIDITY   IN   THE   TERRITORY 

Africa,  among  the  European  population. 

IN  East 

White 
persons. 

Civil 
persons. 

Cases  of  ma 
White. 

aria  among 
Civil. 

Total. 

1903-04 

151 

1,200 

164 

292 

51-3% 

1904-05 

151 

1,340 

171 

461 

66-1% 

1905-06 

198 

1,688 

188 

701 

47-1% 

1906-07 

233 

2,142 

206 

500 

297% 

1907-08 

192               2,734 

156 

614 

1           -* 

25-3% 

1908-09 

3,283 

S92 

27-1% 

Dar-es-Salaam,  who  had  been  examined  since  October  1907 
in  sufficient  numbers  without  being  given  quinine. 

The  results,  concerning  children,  show  clearly  how  much 
more  favourable  the  morbidity  is  among  the  town  children 
who  are  partly  under  quinine  treatment.  This  favourable 
consequence  is  not  only  due  to  a  lesser  danger  of  infection  to 
which  the  children  living  in  towns  are  exposed.  And  this  can 
be  seen  from  the  single  figures  of  morbidity  which  are  higher 
alternatively  in  the  centre  and  at  the  periphery  of  the  town. 
If  the  danger  of  infection  were  less  in  the  centre,  its  figures  of 
morbidity  also  should  be  lower. 

Clearly  enough,  this  difference  is  not  as  pronounced  in  the 
case  of  adults,  in  whom  acquired  immunity  plays  a  considerable 
part.  On  consulting  Table  IV  on  Tanga,  it  is  quite  clear 
that,  under  the  circumstances  prevailing  in  the  seaports  of 
German  East  Africa,  the  malaria  among  the  natives  can  be 
kept  on  a  certain  level  simply  by  methodical  treatment  of  all 


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Sect.  5i]  KAMERUNS  469 

the  infected  persons.  But  the  statistician,  as  well  as  the 
practitioner  in  the  midst  of  his  work,  comes  to  the  conclusion, 
that  a  simple  diminution  does  not  suffice,  and  that  this  diminu- 
tion is  very  fluctuating  and  strongly  influenced  by  incalculable 
factors.  It  is,  therefore,  the  keen  ambition  of  the  medical 
officers  in  Dar-es-Salaam  to  obtain  the  means  necessary  for 
conducting  anti-mosquito  measures  in  the  surrounding  districts 
of  the  town. 

At  present,  engineers  are  engaged  on  surveying  the  town 
and  surrounding  districts  in  order  to  work  out,  on  the  basis  of 
these  measures,  a  plan  for  the  abolition  of  ditches  and  other 
Anopheline  breeding-places. 

(2).  Kameruns. — This  German  territory  had,  and  has  partly 
up  to  this  day,  a  very  bad  reputation  as  a  hot-bed  of  fever.  In 
1896-1897  the  malaria  morbidity  in  Duala,  the  most  important 
seaport,  amounted  to  about  391%  ;  in  certain  months  as  many 
as  70%  of  the  Europeans  became  infected  ;  about  48^  of  the 
Europeans  acquired  blackwater  fever ;  and  the  total  mortality 
caused  by  tropical  diseases  altogether  amounted  to  about  8^ 
(Table  VII). 

TABLE  VII 


Malaria  among  the 

European  troops  in  Kamerun. 

Strength  (Iststarke) 

igoo-oi. 

1901-02. 

1902-03. 

1903-04. 

1904-05. 

1905-06. 

1906-07. 

1907-08. 

91 

85 

71 

87 

84 

92 

89 

Cases  of  malaria    X 

340  = 
370% 

114= 

162% 

104= 

"9% 

131  = 

165% 

131  = 

1-^2% 

87  =  97% 

Deaths       due       to 

malaria 

0 

0 

0 

0 

0 

0 

Cases  of  blackwater 

fever 

20 

18 

21 

23 

8 

13 

9 

Deaths  due  to  black- 

water  fever    . 

2 

2 

3 

0 

0 

... 

I 

Official  statistics  for  the  Kameruns  are  very  incomplete, 
in  consequence  of  the  scattered  nature  of  the  single  stations. 

The  capital  Duala  is  situated  on  a  relatively  favourable 
spot,   z>.,   on   the   brink    of  the   rapid   Kamerun   River,  about 


470  PREVENTION  IN  GERMAN  POSSESSIONS  [Sect. 

6  to  12  metres  above  its  highest  level.  Here  was  therefore 
given  the  possibility  greatly  to  reduce  the  number  of 
Anophelines  through  rainwater  conductors  and  a  regular  system 
of  drainage  of  several  swampy  places.  In  the  latter  years 
Ziemann  has  worked  in  connection  with  the  local  Government 
with  great  energy  at  the  amelioration  of  the  general  hygienic 
conditions.  The  territory  of  the  town  itself  has  been  planned, 
and  cleared  of  all  superfluous  bush  ;  and  by  means  of  straitly 
made  roads  the  wind  is  given  free  passage.  Sewers  effect  rapid 
drainage  of  all  rainwaters.  A  sanitary  brigade  supervises  the 
accurate  and  continued  adherence  to  the  specified  measures. 
The  brigade  extends  its  surveillance  also  over  the  surrounding 
districts  ;  hollows  in  the  neighbouring  wood,  from  where  the 
Anophelines  swarmed  to  the  town,  were  drained  or  filled  up, 
and  if  this  was  not  practicable,  Saprol  was  poured  over  the 
water  surface  at  regular  intervals.  Great  credit  is  to  be  given, 
however,  to  the  Government  medical  officers  for  their  work  of 
furthering  quinine  prophylaxis.  It  was  as  early  as  the  close 
of  the  last  century  when  F.  &  A.  Plehn  recommended  prophy- 
lactic use  of  quinine,  and  since  then  the  value  of  this  method, 
together  with  general  hygienic  improvements,  has  found  full 
recognition  with  the  majority  of  settlers.  Also  mosquito-proof 
houses  are  recommended  and  used  as  an  anti-malarial  measure, 
although  this  method  is  rendered  much  more  difficult  by  the 
humid  climate  which  soon  destroys  the  wire-gauze. 

The  benefit  resulting  from  the  above  measures  can  be  easily 
seen  from  the  figures  indicating  the  malaria  morbidity  for 
Duala  alone : — 


1900-01. 

^87% 

1901-02. 

■30% 

1902-03. 

77% 

Number  of  inhabitants  'j 
District  Duala          .  J 

1902-03. 
142 

1903-04. 
152 

1904-05. 
164 

1905-06. 
183 

1906-07. 
260 

1907-08, 
300 

Hospital  frequented  by 
Hospital  for  malaria    . 

187 
83 

158 
S3 

163 

83 

151 
68 

185 
89 

213 

74 

Malaria  percentage     . 

44'4 

53-6 

50-9 

45 'o 

48-1 

347 

51]  TOGO  471 

In  spite  of  the  increase  of  the  European  population  to  double 
its  previous  strength,  the  number  of  severe  cases  of  malaria 
treated  in  hospital  had,  with  slight  fluctuations,  remarkably 
diminished. 

It  must  be  admitted  that  under  such  measures  also  the 
malaria  among  the  natives  is  bound  to  diminish.  At  the 
policlinic,  quinine  is  distributed  gratis  to  all  natives ;  the 
number  of  those  who  received  quinine  in  1907- 1908  was  820. 
The  treatment  of  so  many  infected  people  in  one  place  is 
sure  to  lower  the  possibility  of  infection  for  the  Anophelines 
and  consequently  the  malarial  infections  in  man. 

The  number  of  Europeans  in  the  other  settlements  in 
Kamerun  is  too  small,  and  is  also  subject  to  too  many 
changes,  to  allow  the  possibility  of  deducting  any  conclusions 
about  the  value  of  certain  anti-malarial  work.  The  favourable 
effect  of  the  malaria  prophylaxis,  and  especially  the  individual 
quinine  administration  (prophylactic),  together  with  general 
improvement  in  hygienic  conditions,  is  evident  anywhere. 

The  same  holds  good  for  the  territory  of  Togo,  with  its  three 
important  places  :  Lome  with  about  6,000,  and  Anecho  and 
Palime  with  about  3,000  inhabitants  each.  The  two  former 
places  are  situated  on  a  line  of  dunes  directly  at  the  sea,  and 
landwards  spreads  a  so-called  lagoon.  During  the  dry  season, 
from  October  to  April,  there  is  so  little  malaria  in  Lome  that 
Dr  Kriiger  (no  reference)  recommends  to  suspend  the  quinine 
prophylaxis  during  that  time.  When,  however,  in  April  or 
May  the  rainy  season  commences,  the  malarial  infections  soon 
reappear,  for  the  innumerable  little  hollows  in  the  bed  of  the 
richly  vegetated  lagoon  now  fill  up,  and  the  Anophelines  rapidly 
increase. 

At  places  with  such  pronounced  "malaria  seasons"  the  quinine 
prophylaxis  must  be  given  first  consideration.  In  Togo  it  is 
religiously  practised  by  many  Europeans,  though  not  by  all, 
as  in  1 907- 1 908  still  99  infected  Europeans  required  medical 
attendance,  61   of  whom,  however,  contracted  the  disease  "in 


472  PREVENTION  IN  GERMAN  POSSESSIONS  [Sect. 

the  bush,"  The  work  of  a  mosquito  brigade  is  making  for 
the  diminution  of  the  gnats  {Stegomyid)  within  the  town  and 
surrounding  districts,  whilst  drainage  of  the  lagoon  has  only 
just  been  decided  upon. 

(3).  German  South-west  Africa. — This  territory  has  badly 
suffered  from  disturbances,  so  that  no  precise  statistics  exist  for 
this  time.  In  1907- 1908  about  3,000  soldiers  were  sent  home, 
and  about  3,400  Europeans  remained  in  March  1908.  Among 
the  latter  occurred  507  cases  of  malaria  with  one  death,  and  4 
cases  of  blackwater  fever,  one  of  which  with  lethal  exitus.  The 
malaria  is  more  general  in  the  north  of  the  protectorate  which 
projects  into  the  tropics  and  possesses  a  pronounced  rainy 
period,  the  rainfall  measuring  from  400  to  700  mm.  per  annum 
(December  till  May).  During  this  short  period  the  Anophelines 
multiply  enormously  in  the  numerous  puddles  and  pools,  even 
in  the  footprints  of  horses  and  wild  animals  and  the  leaf-axils 
of  certain  plants.  As  water  is  there  a  question  of  great 
economical  importance,  petrolisation  is  not  practicable,  as,  for 
instance,  in  the  case  of  watering-places  for  cattle.  The  only 
measure  to  be  taken  into  consideration  seems  to  be  fumigation. 

During  1906-1907  a  proper  quinine  prophylaxis — every  fifth 
and  sixth,  respectively  eighth  and  ninth  day  a  O'5-ro  gramme 
dose — was  practised  under  the  supervision  of  the  local  medical 
officers  in  the  following  stations  :  Namutoni,  Zesfontain, 
Grootfontain,  Waterberg,  Outjo,  Otavi  and  Omaruru.  The 
result  was  a  very  unfavourable  one  :  i  r6  to  90%  of  the  persons 
treated  suffered  from  malaria ;  in  four  stations  more  than  75%. 

The  reason  for  this  non-success  has  not  been  quite  explained, 
as  since  1907  no  further  report  has  been  published.  In  many 
places  it  has  been  stated  that  the  quinine  tablettes  were  not 
quite  soluble  ;  and  it  is  probable  that  the  form  of  malaria  in 
question  was  of  the  most  virulent  type,  against  which  the 
quinine  was  but  of  little  use.  The  infection  was  mostly  very 
slight. 

It  will  be  necessary  to  continue  exact  observations  for  many 


5i]  SOUTH    SEAS  473 

years  before  one  can  possibly  determine  for  what  reason  the 
quinine  prophylaxis  has  failed  just  here.  At  the  time  any 
judgment  upon  this  single  observation  would  be  premature. 

(4).  The  German  possessions  in  the  South  Sea. — The  colonies 
in  these  regions  are  relatively  small,  and  so  is  the  number  of 
Europeans.  Only  few  medical  officers  are  in  practice  there, 
and  consequently  the  statistic  material  can  add  but  little  to 
what  has  been  said  above. 

It  is  worth  mentioning  that  Koch  found  only  quartana  on 
the  "  French  Islands "  (Bismarck-Archipel),  and  only  tropica 
in  Maty.  Some  groups  of  islands  are  completely  free  from 
malaria. 

The  results  of  anti-malarial  measures  in  the  German  Colonies 
can  be  briefly  stated  as  follows : — 

1.  The  simplest  and  cheapest  method  has  been  found  to 

be  quininisation. 

2.  With  carefully  -  practised  and  well-supervised   quinine- 

therapy  and  prophylaxis  it  is  possible  to  exterminate 
malaria  even  in  very  badly-infected  places. 

3.  Individual  prophylaxis  with  quinine  suffices  in  suscept- 

ible persons  (Europeans)  to  prevent  with  great 
certainty  an  outbreak  of  malaria.  According  to 
the  probability  of  infection  in  a  certain  place,  this 
prophylaxis  must  be  increased  or  diminished. 

4.  Anti  -  malarial   measures  in   the  form  of  quinine  treat- 

ment of  infected  persons  have  led  to  a  decrease 
in  the  malaria  morbidity,  wherever  they  have 
been  practised  regularly,  and  for  a  sufficiently 
long  period. 

5.  The  steadier  the  native  population  of  a  place,  the  easier 

it  will  be  to  find  out  all  infected  people  and  treat 
them  thoroughly. 

6.  Quinine  must  be  distributed  gratis,  and  directly  offered 

to  the  natives. 

7.  The  treatment  of  infected  persons  with  quinine,  according 


474  PREVENTION  IN  GERMAN  POSSESSIONS      [SECT.  51 

to  Koch,  is  sufficient  to  keep  the  malaria  on  a  low 
level  among  the  natives  in  tropical  towns. 

8.  The  treatment  of  the  natives  with  quinine  together  with 

individual  prophylaxis  leads  to  a  remarkable  decrease 
in  the  malaria  morbidity  among  Europeans. 

9.  In   many  cases  quininisation  alone  will   not   suffice   to 

reduce  the  morbidity  to  a  degree  which  is  desirable 
in  the  politico-economic  interest. 
10.  Which  one  of  these  three  anti-malarial  measures,  quinin- 
isation, mechanical  protection,  and  anti  -  mosquito 
measures,  is  the  most  important  can  only  be  decided 
upon  according  to  the  local  conditions. 


Par  le  Dr   EDMOND   SERGENT  (Alger) 

52.    Campagrnes    Antipaludiques    en    Territoire    Fran(?ais. 

— Le  paludisme  n'existe  plus  en  France  que  sur  de  rares  points 
ou  il  s  eteint  d'ailleurs  peu  a  peu  :  la  Vendee,  la  Sologne,  la 
Camargue. 

La  culture  intensive  succedant  a  de  grands  travaux  d'assain- 
issement  agricole,  I'accroissement  du  bien-etre  et  de  I'instruction 
generale  peuvent  expliquer  en  partie  ce  recul  du  paludisme  sur 
le  territoire  de  la  mere-patrie,  mais  il  est  difficile  d'en  preciser 
retrospectivement  d'une  fa^on  parfaite  toutes  les  causes.  La 
survivance  des  Anophelines  au  paludisme  dans  la  France  entiere 
est  un  fait  tres  net  qui  montre  que  le  paludisme  peut  disparaitre 
sans  que  son  vecteur  soit  extermine. 

Malheureusement  la  France,  grande  puissance  coloniale,  a 
dans  ses  possessions  d'au  dela  les  mers  un  ennemi  toujours 
present  dans  le  fleau  paludeen. 

L  Campagnes  a^itipaludiques  en  Algerie. — La  plus  belle  de  ces 
colonies  a  vu  son  sort  longtemps  discute,  non  seulement  pour 
des  raisons  politiques  diverses,  mais  surtout  a  cause  de  son 
insalubrite  qui,  croyait-on,  devait  en  rendre  a  jamais  le  sejour 
impossible  aux  races  europeennes,  Alger  etait  occupe  en  1830, 
et  en  1841  le  General  Duvivier,  un  heros  de  la  conquete, 
ecrivait  la  phrase  fameuse :  "  Jusqu'a  present,  les  cimetieres  sont 
les  seules  colonies  toujours  croissantes,  que  I'Algerie  presente."^ 
C'est  en  Algerie  que  le  Professeur  A.  Laveran  devait  decouvrir, 
en  1880,  I'agent  de  la  fievre  paludeenne  et  etablir  ainsi  sur 
une  base  reellement  scientifique   1  etude  de  cette  affection  en 

1  General  Duvivier,  "Solution  de  la  Question  de  I'Algerie."     Paris,   1841,  p.  4, 
Cette  solution,  c'etait  I'evacuation,   p.   49. 

475 


476         ANTIPALUDIQUES  EN  TERRITOIRE  FRANCAIS    [Sect. 

meme  temps  qu'il  ouvrait  un  nouveau  chapitre  de  la  microbi- 
ologic, celui  des  microbes  pathogenes  Protozoaires.^  C'est  aussi 
en  Algerie  qu'un  autre  medecin  militaire :  F.  C.  Maillot,  des 
1834,  apportait  de  I'ordre  dans  la  determination  des  fievres 
continues  des  pays  chauds,  et,  malgre  de  vives  attaques  de 
I'ecole  broussaisienne,  demontrait  d'une  facon  definitive  quelles 
sont  les  regies,  jusqu'alors  insoupconnees,  qui  doivent  presider 
a  la  medication  quinique.^  Deux  chimistes  frangais,  Pelletier 
et  Caventou,  avaient  rendu  possibles  les  beaux  travaux  de 
Maillot  en  isolant  I'alcaloide  du  quinquina.  C'est  a  Maillot 
que  I'Algerie  doit  d'etre  devenue  frangaise ;  et  le  Dr  Battarel 
a  pu  dire  qu'il  a  complete  de  la  facon  la  plus  heureuse  la 
formule  du  Marechal  Bugeaud  :  ense  et  aratro  en  y  ajoutant : 
et  quina. 

L' Algerie  etait  devenue  habitable,  mais  le  progres  normal 
de  I'assainissement  y  est  lent.  Encore  a  present,  beaucoup  trop 
de  vies  et  d'energies  y  sont  consumees  du  fait  du  paludisme. 
C'est  pourquoi,  a  I'annonce  de  la  belle  decouverte  de  R.  Ross, 
sur  le  role  des  moustiques  dans  I'etiologie  paludeenne,  I'lnstitut 
Pasteur  de  Paris  envoya,  en  1902,  une  mission  antipaludique, 
dont  les  essais  furent  poursuivis  d'abord  sur  les  reseaux  de 
Chemin  de  Fer.  Mais  des  1904  M.  le  Gouverneur  -  General 
Jonnart  demanda  a  M.  Roux,  Directeur  de  I'lnstitut  Pasteur 
de  Paris,  d'etendre  ces  essais  aux  localites  les  plus  paludeennes 
de  toute  I'Algerie ;  il  leur  temoigna  une  precieuse  sollicitude, 
et  les  appuya  constamment  de  sa  haute  autorite. 

Territoire.  —  L'Algerie  occupe  une  surface  approximative 
de  300,000  kilometres  carres.  La  partie  habitable  figure  un 
parallelogramme  allonge  de  Test  a  I'ouest  entre  le  Sahara  et  la 
Mediterranee.  Sur  le  bord  meme  de  la  mer  surgissent  des 
chaines  de  montagnes  dirigees  egalement,  d'une  facon  generale 
de  Test  a  I'ouest  et  dont  les  sommets  depassent  rarement  2,000 

^  A.  Laveran,  "  Traite  du  Paludisme."     Paris,  2eme  ed.,  1907. 
2  Le  Professeur  Trolard  a  reuni  un  certain  nombre  des  oeuvres  de  Maillot  dans 
un  ouvrage  de  260  pages.     Paris,  1894,  chez  Doin. 


52]  LOCAL  CONDITIONS  477 

metres.  Entre  ces  montagnes  ou  entre  leurs  contreforts 
s'ouvrent  des  vallees  et  des  plaines  (vallees  de  la  Seybouse,  de 
la  Soummam,  du  Cheliff,  plaines  de  la  Mititdja,  de  la  Macta, 
Hauts  Plateaux),  qui  constituent  autant  de  regions  distinctes 
par  leurs  caracteres  de  geographie  physique.  La  faune,  la  flore, 
la  climatologie  sont  ceux  du  bassin  mediterraneen.  Une  assez 
etroite  bande  littorale  limitee  au  Sud  par  la  ligne  qui  correspond 
aux  chutes  d'eau  minima  annuelles  de  40  cm.  represente  la 
partie  colonisable  par  les  Europeens.  Plus  au  Sud  c'est  le 
steppe,  pays  des  Nomades,  du  mouton  et  du  chameau.  Plus 
au  sud  encore  c'est  le  desert  du  Sahara,  a  climat  continental, 
et  qui  s6pai-e  davantage  I'Algerie  de  I'Afrique  que  la  mer  ne 
la  separe  de  I'Europe. 

En  raison  de  la  faible  hauteur  des  montagnes  et  de  I'absence 
des  neiges  eternelles,  le  regime  des  cours  d'eau  {oued  en  arabe) 
est  essentiellement  torrentueux.  Les  marecages  des  plaines 
basses  et  les  mares  subsistant  en  et6  dans  le  lit  des  oueds  sont 
les  principaux  gites  a- Anophelines. 

Habitants. — Sur  ce  vaste  espace  habitent  (recensement  de 
1906)  5,231,850  ames,  dont  729,960  Europeens  et  4,501,890 
indigenes,  les  premiers  agglomeres  surtout  dans  les  villes  et 
les  villages,  les  seconds  epars  dans  la  campagne.  Les  indigenes, 
tous  de  race  blanche  :  Arabes  ou  Berberes  arabises  dans  les 
plaines,  Berberes  dans  les  montagnes  ou  le  desert  (Kabyles  de 
la  grande  et  de  la  petite  Kabylie,  Chaouias  de  I'Aures,  Touareg 
du  Sahara),  possedent  souvent  ainsi  que  je  I'ai  montre  avec 
mon  frere,  une  certaine  immunite  relative  centre  I'hematozoaire 
du  paludisme,  qui  leur  permet  d'heberger  ce  mJcrobe  dans  leur 
sang  peripherique,  sans  presenter  de  symptomes  morbides 
(exactement  comme  les  populations  negres  de  I'Afrique  d'apres 
ce  qu'  avaient  deja  vu  R.  Koch,  Stephens  et  Christophers). 
Cet  etat  d'immunite  relative  ou  de  paludisme  latent  est  tres 
dangereux  pour  la  collectivite  car  ces  "  porteurs  d'hemotozo- 
aires"   qui   souffrent  peu,  eux-memes,  en  etat  normal,  de  leur 


478         ANTIPALUDIQUES  EN  TERRITOIRE  FRANCAIS     [Sect. 

infection,  sont  toutefois  susceptibles  d'infecter  a  tout  moment 
les  Anophelines. 

Les  sujets  exposes  au  paludisme  sont  done  en  premier  lieu 
les  colons  immigrants,  et  les  indigenes  provenant  de  regions 
saines.  Le  degre  de  danger  couru  par  eux  depend  surtout  du 
voisinage  d'indigenes  en  etat  de  paludisme  latent,  car  il  y  a 
des  Anophelines  partout  en  Algerie,  sauf  dans  les  grandes 
villes.  Le  peril  pour  les  colons  etablis  dans  une  exploitation 
provient  de  ce  que  I'infection  ne  reste  pas  unique,  mais  est 
suivie,  en  regie,  de  reinfections  successives  qui  se  produisent 
avant  que  I'immunite  relative  ait  pu  etre  acquise.  Les 
Europeens  qui  resistent  a  ces  reinfections  presentent  ensuite, 
comme  les  indigenes,  une  immunite  relative  coexistant  avec 
un  paludisme  latent. 

Anophelines. — Les  Anophelines  de  I'Afriquedu  Nord  actuelle- 
ment  connus  sont  :^ — Anopheles  maculipenms  Meigen,  I'espece  la 
plus  repandue.  On  le  trouve  partout  sauf  dans  les  villes ;  il 
habite  le  littoral,  les  plaines,  les  montagnes,  les  vallees,  le  steppe, 
le  Sahara.  En  moyenne  4%  sont  infectes  dans  les  pays 
paludeens. 

A.  algeriensis  Theobald,  espece  vicariante  de  H.  bifurcatus 
espece  sylvane,  farouche.  On  le  trouve  aussi  infecte  par  des 
sporozoites  de  Plasmodium. 

Pyretophorus  myzomyifacies  Theob.  et  Serg.  Vallees  des 
regions  accidentees.  On  le  trouve  egalement  infecte  par  des 
sporozoites  de  Plasmodium. 

Pyretophorus  sergenti  Theob.  Lisiere  des  Steppes  et  du 
Sahara. 

Pyretophorus  chaudoyei  Theob.  (etudie  par  A.  Billet),  Sahara. 

Une  premiere  epidemic  de  tierce  benigne  apparait  au 
printemps,  la  tierce  maligne  predomine  en  ete  et  en  automne. 
La  quarte  se  montre  surtout  en  automne  et  surtout  dans 
certaines  contrees. 

1  Voir  Annales  Institut  Pasteur,  t.  xix.,  1905,  pp.  246  sq.  ;  t.  xx.,  1906,  p.  248. 
C.  R.  Soc.  Biologic,  pp.  246,  1905,  p.  499.  F.  V.  Theobald,  "  Monograph  of 
Mosquitos"  (iv.  tomes),  London. 


52]  INDIVIDUAL   PROPHYLAXIS  479 

Mesures   prophylactiques. — Nous    les    classons    dans    I'ordre 
suivant : — 


A         EloigJiefnent  des  gites  a  Anophelines 
Eloignement  du  Reservoir  de  virus 

B         Grandes  mesures  antilarvaires 
Petites  mesures  antilarvaires    . 

Mesures  centre  les  adultes 

C         Quininisation  preventive  . 
Quininisation  curative 

D         Defense  mecanique  personnelle 
Defense  mecanique  collective  . 


Ces    diverses    mesures,   partant   de    principes    divers    pour 
aboutir  au  meme  but,  sont  utilisables  a  des  degres  differents 
selon  que  Ton  se  trouve  dans  I'un  de  ces  trois  cas  : — 
(i)  Prophylaxie  antipaludique  d'un  particulier. 

(2)  „  „  d'une  collectivity. 

(3)  »  »  del'Etat. 

(i).  Prophylaxie  dun  particulier.  —  Dans  les  nombreux 
voyages  que  nous  avons  faits  a  travers  les  regions  les  plus 
paludeennes  de  I'Algerie,  nous  sommes  restes  toujours  indemnes 
du  paludisme  en  observant  les  precautions  suivantes : — Autant 
que  possible,  passer  la  nuit  loin  des  agglomerations  indigenes 
et  des  gites  a  Anophelines.  Prendre  tous  les  jours  une  dragee 
de  0*20  centigrs.  de  bichlorhydrate  de  quinine  (enrobee  dans 
0'30  centigrs.  de  sucre),  pendant  tout  le  temps  que  Ton  passe 
en  pays  infecte,  et  pendant  15  jours  apres  la  rentree  en  pays 
sain.  Parfois,  en  pays  tres  palud6en,  nous  prenions  0*40 
centigrs.  par  jour,  une  dragee  a  chaque  repas.  Enfin  nous 
n'avons  jamais  dormi  en  pays  paludeen,  soit  la  nuit,  soit  a 
I'heure  de  la  sieste,  sans  notre  moustiquaire  portative  que  nous 
emportons  toujours  dans  nos  bagages  et  que  nous  montons  tou- 
jours nous-memes. 

Un  certain  nombre  d'ofificiers,  de  fonctionnaires  ou  de  colons 
contraints  a  traverser  des  regions  fievreuses  ont  adopte  la 
pratique   de   ces   mesures   de    preservation    personnelle.     Celle 


48o         ANTIPALUDIQUES  EN  TERRITOIRE  FRANCAIS     [Sect. 

qui  est  le  plus  frequemment  observee  est  la  quininisation 
preventive. 

(2).  Vne  collectivite  (compagnie  de  chemins  de  fer,  exploita- 
tions agricoles,  minieres,  grandes  administrations)  doit  eviter 
d'installer  ses  postes,  ses  gares,  dans  le  voisinage  des  gites  a 
Anophelines  et  des  agglomerations  indigenes.  Le  Service 
antipaludique  en  Algerie  est  consulte  en  principe  chaque  fois 
que  I'on  construit  une  ligne  de  chemin  de  fer  et  que  Ton 
fonde  un  nouveau  village  de  peuplement  europeen.  On  a  pu 
faire  prevaloir  parfois  le  choix  de  certains  emplacements  moins 
exposes  que  d'autres  a  la  contagion  paludeenne. 

Les  collectivites  (agents  de  chemins  de  fer  et  des  Services 
publics,  troupes,  ouvriers  agricoles,  mineurs,  etc.)  peuvent  dtre 
facilement  soumises  a  une  quininisation  preventive  par  les  petites 
doses  journalieres.  II  est  bon  dans  ces  cas  de  faire  tenir  un 
registre  des  prises  de  quinine  pour  que  Ton  sache  bien  comment 
est  absorbe  le  medicament. 

Enfin  ces  collectivites  peuvent  etre  egalement  protegees  par 
les  grillages  metalliques  poses  aux  ouvertures  des  habitations : 
defense  tnecanique  collective. 

C'est  la  un  procede  de  luxe  qui  coute  fort  cher  et  ne  peut 
etre  propos6  qu'en  faveur  de  personnes  d'un  niveau  social  assez 
eleve  pour  prendre  soin  de  leur  confortable.  Nous  tachons  de 
rendre  cette  defense  mecanique  le  plus  automatique  possible, 
pour  demander  tres  peu  d'attention  et  de  bonne  volonte  aux 
occupants  des  habitations,  C'est  ainsi  que  nous  faisons  etablir 
les  volets  a  I'interieur  des  fenetres  de  facon  a  ce  que  le  grillage 
des  fenetres  soit  exterieur  a  tous  les  battants,  et,  par  consequent, 
n'ait  pas  besoin  d'etre  perce  de  lucarnes  pour  le  maniement 
des  verrous,  crochets  au  fleaux  destines  a  assujetir  les  volets. 
Si  les  volets  sont  exterieurs,  par  exemple  dans  les  maisons 
deja  construites  que  Ton  veut  grillager,  nous  preferons  pour 
les  grillages  les  chassis  a  guillotine  dont  la  fermeture  est 
automatique. 


Fig    1. 


1".    C.    MAILLOT. 


I'lG.    4. 


GITE    A    AN01'Ili:i.INK    DANS    UNE   OASIS    SAIIAKIKN'MC. 


Fig.  5. 


par  (/rs  y/yy/<n/rs , 


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Fic.  6. 


DEFENSE   MKCANIQUE    (POKTES    KT    FENETRES   GKILI-AGEES). 


Fig.  7. 


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EXAMINATION   OF  CHILDREN. 


Librsirie  CH.  DELASRAVE 


CONTRE  LE  PALUDISME 


Ooolrvililn.onil  SfPCiMl 
»/  tUenne  SERSZilJ 


Lcs  MoiisliqiH's  qui  iii(inil(Mil\l(\Palii(lisiii('  soul  Ics  \iioj>lh'h's 


CULEX   (CULICINEI 


Comment  on  se  prole<(c  contrc  to  Paludisme 


cow.uc>T  Dime  iiu 

pmnUU  D'lllE  IVTIE  IW 


^ 


Le*  AQopbete«  en  piquant  dt-s  Bt-vmux,  suf-nl.  avi-r  !<■  unu.  Ic  microbe 
de  la  fi^vre.  qu'iia  peuvi^ut  fa&uLin  mocalcr  &ux  autr<^  pHraonnta  qu  ils  piqueot. 

Poor  ^Tiier  ies  fi^vp.-s  palud6«nDes.  tl  fBot  dune  m  proi^:gt^r  ooiitr«  !«• 
Moustiques 

r.->mme  l^^  Wtv^b  de  ceux-cj  vivent  duis  lV«u  sUgnanb-  dus  mar«*.  de* 
M&n^m,  etc..  il  fkul  uL(u>i>J<.i  ■■.  i  iTmn-s  ^utDfrs.  tfic  .  <>u.  8i  oeU  e«\  impossible. 
en  p4troler  la  Barfice  loua  la«  quinxe  jour»  eu  ♦•U;  i  10  ~  H.-  p.'lrol*-  par  mfttre 
OMT*  de  •urfar*  de»u).  Lea  lir»e«  sont  aaphyiitea  par  ie  p^irole  qnelU* 
Aspir-nl  en   Ten»ni    r-^pirer  «i   U  surfac* 


oe«1  p«a  9)^r  de  dftruirv  t>~>ult«  liv  lar- 
Mousbque*.  on  se  proWKo  i-onlre  !«»«  HouiUquci  kJulw*  qui  s>'>ni 
AclOA  dr«  aymphea,  en  ^amis*«ni  \f\  purtea .  U«  rt>D(>tn«  ti  Ifs 
ouverliir«a  d*«  chemin^^«.  de  gnkl«K(.-«  i-n  toile  metklliqur  de  1,5  i 
2"   de    lsr^<-ur   de    tOftille. 

11  «at  hon  uiiui  de  pr*odrv  pn'v«Qti*enu-Dt  de  la  quiniDc 
(30  oenUj{r«mni<-«  par  jour  pour  un  adulu.-).  Ci-iu>  fatbtc  doae.  priar 
rt^gniti^rvmfol    WuB    k^a  joura.    iih    fati^fue    pas.   ••i   »'11*»   no(   tffiiAi-- 


llCi.    o.      .SA.Ml'I.l-.    CHART    FuK    PUBLIC    IN.STKLCTION. 


[  To  face  page  480. 


52]  MAJOR   MEASURES  481 

(3).  Le  role  de  t&tat  dans  la  prophylaxie  antipaludique 
peut  etre  compris  ainsi : 

Execution  des  gr-andes  mesures  antilarvaires : — Canaux  de 
dessechement,  grandes  plantations  dans  les  marais,  reboisement 
des  montagnes,  petits  barrages  dans  les  hauts  bassins,  regular- 
isation  des  cours  d'eau,  surveillance  des  barrages,  reservoirs, 
etc.  Mais  ces  enormes  travaux,  qui  coutent  tres  cher,  ont 
toujours  un  but  principal  d'assainissement  agricole ;  I'hygiene 
antipaludique  ne  peut  intervenir  ici  qu'a  titre  accessoire,  pour 
appuyer  tel  projet,  contre-indiquer  tel  autre.  D'ailleurs  ces 
grandes  mesures  antilarvaires  ne  sont  pas  completement 
efficaces  par  elles-memes  ;  elles  ne  font  que  rendre  possibles 
les  petites  mesures  antilarvaires  et  surtout  la  bonification 
agricole.  Celle-ci,  en  drainant  et  en  permeabilisant  le  sol,  en 
supprimant  les  moindres  mares,  en  utilisant  toute  I'eau  des 
pluies  et  toute  I'eau  des  sources,  aboutit,  en  poursuivant  un 
but  purement  cultural,  a  un  resultat  reellement  antipaludique. 
Nous  avons  souvent  constate  qu'un  grand  canal  de  desseche- 
ment est  surpeuple  de  larves  d'Anophelines,  tout  comme  le 
marais  qu'il  remplace.  Mais  le  marais  etait  inaccessible,  tandis 
que  des  deux  berges  du  canal  on  peut  atteindre  et  detruire 
les  larves  d'Anophelines. 

Cet  exemple  montre  bien  ce  que  sont,  a  notre  sens,  les 
petites  mesures  antilarvaires.  Dans  le  canal  dont  il  s'agit, 
les  larves  reapparaitront  constamment,  quoiqu'on  fasse,  car  il 
aura  toujours  de  I'eau,  puisque  c'est  son  office  de  drainer  I'eau 
des  couches  superficielles  du  sol.  D'autre  part  il  viendra 
toujours  des  Anophelines  femelles  pondre  sur  cette  eau  tran- 
quille,  car  si  loin  que  Ton  recule  les  limites  des  mesures  anti- 
larvaires, elles  ne  pourront  pas  englober  toute  I'Afrique  du 
Nord.  Par  consequent  les  mesures  de  destruction  des  larves 
devront  etre  repetees  indefiniment  sur  les  parties  du  canal 
voisines  de  lieux  habites  (dans  un  rayon  de  un  kilometre  et 
demi)  et  c'est  la  le  principal  caractere  des  petites  mesures 
antilarvaires :    de   n'avoir   qu'une   efficacite   temporaire.     Elles 

2  H 


482        ANTIPALUDIQUES  EN  TERRITOIRE  FRANCAIS     [Sect. 

tiennent  purement  et  simplement  en  6chec  la  pullulation  des 
larves  pendant  le  temps  ou  elles  sont  mises  a  execution.  On 
a  done  interet  a  maintenir  indemnes  de  larves  les  environs 
d'une  agglomeration  importante,  mais  il  faut  evidemment  que 
la  valeur  economique  du  groupement  a  defendre  soit  assez 
grande  pour  justifier  les  depenses  engagees.  II  est  une  autre 
utilite  des  petites  mesures  antilarvaires,  c'est  celle  de  supprimer 
temporairement  les  vecteurs  de  la  contagion  et,  par  suite, 
d'empecher  pendant  ce  temps  les  reinfections.  Elles  permettent 
ainsi  la  guerison  des  anciens  infectes,  que  Ton  aide,  d'autre 
part,  par  la  quininisation  curative.  En  resume,  a  mon  sens,  les 
petites  mesures  antilarvaires  auront  pour  but,  non  pas  seulement 
d^eviter  les  infections  des  indemnes,  vtais  aussi  de  permettre  la 
guerison  des  anciens  infectes. 

Le  type  des  petites  mesures  antilarvaires  est  presente  par 
les  faucardements  des  eaux  stagnantes  repetes,  suivant  les 
besoins,  2  ou  3  fois  par  an,  et  les  petrolages,  renouveles  tous 
les  quinze  jours  (tous  les  8  jours  au  Sahara).  Mais  les  minimes 
artifices,  qui  rendent  impossible  la  vie  des  larves  dans  les 
aquariums  parfois  tres  reduits  qui  leur  suffisent,  peuvent  etre 
varies  a  I'infini.  Je  citerai  comme  un  exemple  typique  le 
procede  suivant  que  nous  avons  applique  deja  souvent. 

Soit  une  source,  une  fontaine,  un  abreuvoir,  dont  I'eau 
d'ecoulement  forme  des  gites  intarrissables  et  permanents. 
Nous  faisons  creuser,  au  lieu  d'un  seul  canal,  deux  petits 
canaux  d'ecoulement  fermes  a  leur  origine  par  une  vanne.  On 
laisse  I'eau  s'ecouler  par  un  seul  canal  pendant  huit  jours :  les 
oeufs  y  sont  pondus,  les  larves  naissent,  se  developpent.  Au 
bout  de  huit  jours  nous  baissons  la  vanne  de  ce  canal  et 
ouvrons  I'autre :  les  larves  qui  ne  sont  meme  pas  encore  arrivees 
a  la  nymphose  meurent  sur  la  boue  qui  seche  au  fond  du  canal 
abandonne  par  I'eau.  Ainsi,  sans  aucune  surveillance,  cinq 
minutes  de  travail  toutes  les  semaines  suffisent  a  empecher 
tout  developpement  des  larves  dans  cette  eau  d'ecoulement. 

Les  mesures  contre  les  adultes  telles  que  les  fumigations  de 


52]  QUININE  483 

poudre  de  pyrethre  ou  de  soufre,  la  pulverisation  de  poudre  de 
pyrethre  ou  de  petrole,  les  trous-pieges  de  Blin,  jouent  un  role 
tres  secondaire  dans  la  lutte  antipaludique. 

C'est  au  contraire  la  quininisation  airative  que  I'Etat  peut 
appliquer  en  grand  et  faire  servir  le  plus  efficacement  a 
I'assainissement  d'une  region  en  Algerie.  Nous  dirons  d'abord 
que  dans  notre  pratique  nous  organisons  la  quininisation 
curative  exactement  comma  la  quininisation  preventive.  II 
faut,  en  effet,  reserver  aux  m^decins  le  traitement  des  fievreux, 
vraiment  medical,  c'est  a  dire  celui  qui  procede  par  des  fortes 
doses.  D'autre  part,  il  est  bien  plus  commode  d'avoir  une 
technique  unique  qui  s'applique  aussi  bien  aux  sujets  indemnes 
qu'aux  anciens  infectes  dans  un  pays  oil  le  paludisme  est  aussi 
commun.  Enfin  la  comparaison  des  index  endemiques  par  la 
palpation  des  rates  avant  et  apres  les  campagnes  antipaludiques 
nous  demontre  la  reelle  efficacite  des  petites  doses  journalieres 
longtemps  repetees.  D'ailleurs  on  sait  que  meme  les  petites 
doses  de  quinine  sufifisent  a  faire  disparaitre  les  parasites  du 
sang  peripherique  bien  avant  la  guerison  totale  de  I'infection 
palud6enne.  Les  individus  ainsi  "  blanchis,"  alors  meme  qu'ils 
ne  sont  pas  encore  gueris,  sont  deja  rendus  inoffensifs  pour  la 
collectivite.  Au  moment  oii  les  procedes  de  la  quininisation 
preventive  et  curative  sont  mis  en  ceuvre  de  plus  en  plus  dans 
tous  les  pays  paludeens,  on  nous  permettra  de  rappeler  que 
depuis  longtemps  en  Algerie,  a  la  suite  de  Maillot,  les  medecins 
civils  et  les  medecins  de  I'armee  ont  preconise  et  applique  ces 
deux  sortes  de  quininisation.  Je  citerai,  parmi  les  experiences 
les  plus  nettes,  celles  de  Sezary^  et  celles  de  Cornebois.^ 
Sezary  ecrit  en  1891  :  "J'ai  fait  prendre  du  ler  Juillet  au  ler 
Decembre,  tous  les  jours,  a  Tun  des  repas  1 5  centigrammes  de 
quinine,  quelquefois  20,  mais  jamais  davantage.  Avec  cette 
dose  infime,  j'ai  maintenu,  depuis  deux  ans,  en  divers  centres, 

1  "Prophylaxiede  la  Malaria  par  la  Quinine."     Alger,  Jourdan,  i6  pp.,  21  Octobre 
1891. 

2  "  Contribution  a  I'Etude  de  la  Prophylaxie  de  la  Malaria  par  la  Quinine."    These 
tnedecine,  Montpellier,  1894, 


484       ANTIPALUDIQUES   EN   TERRITOIRE   FRANCAIS    [Sect. 

tres  malsains,  des  families  entieres  en  parfait  etat  de  sante,  au 
milieu  de  voisins  toujours  malades.  Et  non  seulement  les  acces 
disparaissent,  mais  I'appetit  augmente,  les  couleurs  du  visage, 
Tembonpoint  reviennent,  en  un  mot,  c'est  I'apparence  de  la 
sante  parfaite  .  .  .  tantis  qu'autour  de  ces  personnes  tout  le 
monde  subit  les  influences  facheuses  du  milieu." 

Cornebois  arrive  en  1894  exactement  aux  memes  con- 
clusions :  "  L' Administration  de  petites  doses  quotidiennes  de 
quinine  a  pour  resultat  de  prevenir,  soit  I'invasion,  soit  le  retour 
du  paludisme." 

Les  medecins  de  I'armee  emploient  depuis  longtemps  en 
Algerie  la  quininisation  reguliere  preventive,  et  les  resultats 
dependent  du  soin  qu'on  apporte  a  observer  leurs  prescriptions. 

Le  Service  antipaludique  en  Algerie  emploie  des  dragees 
lenticulaires  roses  de  bichlorhydrate  de  quinine,  semblables  a 
celles  de  I'Etat  italien  et  contenant  vingt  centigrammes  de 
sel  comprimes  et  enrobes  dans  trente  centigrammes  de  sucre. 
Nous  faisons  distribuer  une  dragee  par  jour  aux  adultes  (deux 
dragees  dans  les  regions  tres  paludeennes)  ou  bien  trois  dragees 
tous  les  deux  jours,  ou  tous  les  trois  jours. 

Pour  assurer  une  exacte  administration  de  la  quinine, 
eviter  tout  abus  et  tout  accident,  nous  croyons  necessaire  de 
faire  distribuer  les  dragees  par  des  quininisateurs,  agents  des 
services  publics  ou  personnes  de  confiance,  chargees  temporaire- 
ment  de  ces  fonctions  pendant  I'ete,  moyennant  retribution. 
Les  quininisatrices  sont  encore  plus  precieuses  que  les  quininisa- 
teurs, a  cause  de  leur  facile  acces  aupres  des  femmes  musulmanes. 
Le  quininisateur  distribue  lui-meme  aux  moments  fixes  :  tous 
les  jours,  ou  tous  les  2  jours,  ou  tous  les  3  jours,  la  quinine  aux 
personnes  inscrites  sur  un  registre  ad  hoc.  II  fait  ingerer  les 
dragees  en  sa  presence  et  note  les  prises  sur  son  registre. 

Nous  evaluons  les  resultats  de  cette  quininisation  par  la 
comparaison  des  index  endemiques  avant  et  apres  la  campagne. 
En  regie  generale  ce  sont  les  index  spleniques  que  nous  relevons, 
et,  nous  ne  quininisons,  d'habitude,  que  les  agglomerations  ou 


52]  QUININE  485 

rindex  splenique  depasse,  au  printemps,  15%.  Lorsqu'on  le 
peut,  on  releve  aussi  I'index  hematologique. 

La  quininisation  en  grand  par  I'Etat  est  rendue  difficile  en 
Algerie  par  le  fait  que  ce  pays  est  soumis  comme  la  France 
europeenne  a  la  loi  de  Germinal  an  XI  qui  donne  aux 
Pharmaciens  le  monopole  de  la  vente  de  la  quinine.  II  a  fallu 
done  que  le  Gouvernement  G6n6ral  de  I'Alg^rie  negocie  avec 
les  Pharmaciens  de  la  Colonie  une  entente  aux  termes  de 
laquelle  les  drag^es  de  bichlorhydrate  de  quinine  vendues  au 
public,  sous  des  marques  de  garantie  speciales,  sont  soumies  a 
un  tarif  particulier,  aussi  has  que  possible  quoique  laissant  un 
benefice  aux  Pharmaciens.  Ceux-ci  approvisionnent  de  ces 
dragees  des  depots  de  quinine  confies  a  des  agents  des  Services 
publics  autorises  a  revendre,  au  prix  marque,  les  dragees  au 
public.  D'autre  part  les  Pharmaciens  delivrent  ces  dragees  au 
Service  antipaludique,  pour  la  quininisation  du  Reservoir  de 
virus,  sans  prelever  de  benefice.  En  somme  cette  entente,  si 
elle  donne  ses  fruits,  mettra  a  la  disposition  du  public,  dans 
toute  I'Algerie,  de  la  bonne  quinine,  a  bon  marche,  sous  une 
forme  agreable,  et  permettra  a  I'Etat  d'entreprendre  avec  le 
moins  de  frais  possible  la  quininisation  publique  de  I'enorme 
Reservoir  de  virus  constitu6  par  des  millions  d'indigenes,  en 
majorite  indigents. 

Si  nous  voulons  resumer  le  mode  d'action  de  I'Etat  Algerien 
dans  la  lutte  antipaludique  nous  dirons  que  ses  efforts  princi- 
paux  portent  sur  la  reduction  du  Reservoir  de  virus  forme  par 
les  indigenes  anciens  infectes.  Cette  reduction  du  Reservoir 
de  virus  est  poursuivie  par  la  quininisation  par  petites  doses 
quotidiennes,  et  elle  est  facilitee,  acceleree  dans  toutes  les 
localites  ou  la  chose  est  possible,  par  I'organisation  de  petites 
mesures  antilarvaires. 

Le  service  antipaludique  a  institue  des  campagnes  anti- 
paludiques  exp6rimentales  dans  trois  champs  de  demonstration  : 
un  par  departement :  Montebello  (Alger),  Tourville  (Oran), 
Mondovi  (Constantine).     D'autre  part  il  subventionne  et  aide 


486       ANTIPALUDIQUES    EN   TERRITOIRE    FRANCAIS     [SECt. 

les  campagnes  locales  organisees  suivant  les  memes  principes 
par  les  medecins  collaborateurs  residant  dans  des  villages 
fievreux  et  dirige  les  mesures  prises  sur  les  reseaux  des  chemins 
de  fer,  dans  les  immeubles  administratifs.  Enfin  il  propage  les 
connaissances  nouvelles  sur  I'etiologie  et  la  prophylaxie  du 
paludisme. 

(Une  ligue  algerienne  centre  le  paludisme,  fondee  en  1903 
par  les  Prof.  Moreau  et  Soulie  se  livre  egalement  a  la  vulgarisa- 
tion des  decouvertes  recentes  sur  I'etiologie  et  la  prophylaxie 
du  paludisme.) 

Resultats. — Nous  resumons  ci-dessous  les  resultats  constates 
dans  les  champs  de  demonstration  du  Service  antipaludique. 
lis  donnent  une  idee  des  resultats  obtenus  par  les  diverses 
campagnes  menees  ailleurs. 

(i)  Departenient  d' Alger.—  Montebello  (mesures  antilarvaires 
et  quininisation). 

Avant  la  campagne  : — 

En   1904     75  infectes,   12  indemnes,  il  se  produit   11   leres  infections. 
Apres  la  campagne  : — 

En  1905  44  anciens  infectes,  36  indemnes,  il  se  produit  o  lere  infection. 

„    1906  21         „  „         71  „  „  „       o     „ 

„    1907  13        „  „         65  „  „  „       o     „  „ 

„    1908  20        „  „         54  „  „  „       o     „  „ 

„   1909  18        „  „        68  „  „  „       o    „  „ 

Depuis  le  debut  de  la  campagne  (1905)  il  y  a  eu  a  Monte- 
bello 10  naissances.  Aucun  de  ces  enfants  n'a  eu  le  palu- 
disme jusqu'a  present.  Le  fait  est  unique  dans  I'histoire  de 
Montebello. 

Localites  du  voisinage,  non  defendues,  pouvant  servir  de 
temoins : — 

En  1905       9  Personnes  indemnes,  8  premieres  infections. 
,,   1906     29  cas    graves    de    premiere    invasion    (i     mort    par    acces 

pernicieux). 
„   1907       7  personnes  indemnes,  4  premieres  infections. 
„   1908       3  personnes  indemnes,  i  cas  de  premiere  invasion. 
)>  1909       5  personnes  indemnes,  2  cas  de  premiere  invasion. 


52]  ORAN,   SAINTE    LEONIE,    CONSTANTINE  487 

(2)  Departement  dOran.  —  Tourville  (mesures  antilarvaires 
et  quininisation). 

Avant  la  campagne: — 
En  1905     Sur  82  enfants,  58  grosses  rates  (707%). 

Apres  la  campagne : — 

En  1906     Sur   113  enfants,  26  grosses  rates  (23%).     Sur  900  habitants 

I  Ire  infection. 
„    1907     Sur  65  enfants,  4  grosses  rates  (6'i%).     Sur  1000  habitants 

1  Ire  infection. 

„    1908     Sur  148  enfants,  5  grosses  rates  (3'3%).     Sur  1000  habitants 

o  Ire  infection. 
„    1909     Sur   188  enfants,   8  grosses    rates  (4"2%).     Sur  973  habitants 

o  Ire  infection. 

Depuis  le  debut  de  la  campagne  (1906),  il  y  a  eu  a  Tourville 
106  naissances.  Deux  enfants  seulement  se  contaminerent 
(i  en  1906,  I  en  1907). 

Sainte  Leonie.  —  (Mesures  antilarvaires  et  quininisation — 
celle-ci  defectueuse). 

Avant  la  campagne  : — 

En  1905     Sur  30  enfants,  15  grosses  rates. 
„    1906     Sur  49   enfants,  18   grosses  rates   (36%).     Sur  300  habitants 

2  Ires  infection  dont  une  mortelle. 

Apres  la  campagne  : — 

En  1907     Sur  60   enfants,    16  grosses  rates   (25%).     Sur  300  habitants 

o  Ire  infection. 
„    1908     Sur   78   enfants,  10   grosses   rates   (12%).     Sur  300  habitants 

2  Ire  infection. 
,,    1909     Sur   127  enfants,  7   grosses  rates   (4"i%).     Sur  346  habitants 

o  Ire  infection. 

Localites  du  voisinage,  non  defendues,  pouvant  servir  de 
temoins  : — 

En  1906  14  personnes  indemnesj  14  premieres  infections. 

„    1907  2  „  „  2  „  „     dont  une  mortelle. 

„    1908  I  personne  indemne,  i  premiere  infection. 
„    1909       I  ,,  »  I         ,, 

(3)  D^partement  de  Constantine.  —  Mondovi  (mesures  anti- 
larvaires et  quininisation). 


488       ANTIPALUDIQUES   EN   TERRITOIRE   FRANgAIS    [Sect. 

Avant  la  campagne  : — 

En  1906     Plusieurs  cas  d'hemoglobinurie  et  plusieurs  cas  de  premiere 
invasion  chez  les  nouveau-nes. 

Apres  la  campagne  : — 

En  1907     Sur    773  personnes  3  cas  de  premiere  invasion. 
„    1908      „     1300        „  2      „  „  „ 

»    1909      »    1300        „  2       „  „  „ 

L'index  endemique  de  Mondovi : — 

En  automne  1906  est  de  78"8% 

»  »  1907  „  „  42-5% 
»  »  1908  „  „  32-6% 
»         »         1909    „    „   28-5% 

Localites  voisines,  pouvant  servir  de  temoins  : — 

En  1907  19  cas  de  premiere  invasion. 
„  1908  Nombreuses  rechutes  graves. 
„    1909     Sur  260  personnes,  2  cas  de  premiere  invasion. 

Penthievre. — (Mesures  antilarvaires  et  quininisation). 
Apres  la  campagne  : — 

En  1907     Sur  200  Europeens  2  cas  de  premi&re  invasion  (benins). 
„    1908       ,,     200  „  I  cas  benin  de  premiere  invasion. 

„    1909       „     200  „  o  cas  de  premiere  invasion. 

L'index  endemique  de  Penthievre  : — 

En  automne  1907  est  de  40  % 
»  »        1908    „    „  32-1% 

.1  »        1909    ,,    „  23-5% 

Localites  voisines,  temoins  de  Penthievre : — 

En  1907     I  cas  de  premiere  invasion. 
„    1908     Cas  de  paludisme  nombreux. 
„    1909     Sur  260  personnes.  2  cas  de  premiere  invasion. 

En  1909  ont  ete  distribues,  en  dehors  des  champs  de  demon- 
stration, 450  kilos  de  dragees  de  quinine,  par  les  medecins  col- 
laborateurs  du  Service  antipaludique,  qui  avec  un  zele  et  un 
desinteressement  dont  on  ne  saurait  trop  leur  savoir  gre,  ont 
ajoute  a  leurs  occupations  professionnelles  la  charge  de  com- 


52]  TUNIS  489 

battre  repidemie  la  plus  repandue,  sinon  la  plus  grave  actuelle- 

ment,  en  Algerie. 

Budget  de  la  lutte  antipaludique  en  Algerie. — Depuis  plusieurs 

annees,  les  campagnes  antipaludiques  coutent  au  Gouvernement 

General    environ    cinquante    mille   francs    par   an :    Personnel 

permanent  (avec  frais  de  deplacement)  environ   16,000  francs. 

Personnel  temporaire  (quininisateurs) :  de  3,000  a  4,000  francs. 

Achat  de  quinine:  de  18  a  20,000  francs.     Petites  mesures  anti- 

larvaires :  de    13  a  15,000  francs.      La  defense  mecanique  est 

payee  par  chaque  administration  competente. 

Le  budget  total  de  I'Algerie  est  de  cent  millions  de  francs 

environ. 

II.  Campagnes  antipaludiques  en  Tunisie. — La  Tunisie,  qui 
continue,  a  Test,  I'Algerie,  nourrit  sur  100,000  kilometres  carres 

1,800,000  habitants  dont  1,600,000  indigenes. 

Comme  en  Algerie,  presque  toutes  les  regions  basses  et 
arrosees,  les  plaines  marecageuses,  les  vallees  parsemees  de 
sources  sont  frapp^es  par  le  paludisme  au  printemps  (epidemie 
de  tierce  benigne)  et  en  ete  et  automne  (fievre  maligne  estivo- 
automnale).     Certaines  regions  presentent  de  la  quarte. 

Les  Anophelines  signales  sont:  Anopheles  maculipennis 
Meigen,  Anopheles  algeriensis  Theobald,  PyretopJiorus  cJiaudoyei 
Theobald. 

C.  Nicolle,  apres  une  premiere  experience  de  lutte  anti- 
paludique en  1903,  obtint  la  creation  d'un  service  antipaludique 
rattache  a  I'lnstitut  Pasteur  de  Tunis,  et  qui  fonctionne  regu- 
lierement  depuis  Janvier  1907,  sous  la  direction  technique  de 
Husson.^  Ce  service  a  pour  but  principal  de  defendre  contre 
le  paludisme  les  centres  de  colonisation  en  enseignant  aux 
colons  les  dangers  qu'ils  courent  et  les  precautions  a  prendre 
pour  les  eviter  et  en  renseignant  I'administration  sur  les  mesures 
prophylactiques  d'ordre  general  ou  local  qu'elle  seule  peut  entre- 
prendre.     En  consequence,  des  tournees  sont  faites  dans  un  but 

^  Voir  Archives  de  V Institut  Pasteur  de  Tunis,  depuis  1906,  et  Bulletin  de  la  Soc. 
de  Pathol.  Exotiq.,  t.  i..,  1908,  p.  385  sq. 


490       ANTIPALUDIQUES   EN   TERRITOIRE   FRANCAIS    [Sect. 

de  propagande  et  d'organisation  dans  les  localites  les  plus 
malsaines :  il  faut  citer  en  particuHer  les  defenses  organisees 
sur  les  reseaux  des  chemins  de  fer  et  dans  des  compagnies 
d'exploitation  des  phosphates,  les  reglements  elabor6s  pour  la 
declaration  obligatoire  du  paludisme  dans  la  ville  de  Tunis. 
Pour  un  certain  nombre  de  localites  les  conditions  exactes  du 
paludisme  ont  ete  determinees.  Pour  propager  les  principes 
de  la  lutte  antipaludique,  des  distributions  sont  faites  de 
brochures,  d'affiches.  Enfin  le  service  antipaludique  ainsi  que 
le  gouvernement  tunisien  distribue  gratuitement  des  dragees 
de  quinine. 

Le  privilege  des  pharmaciens  n'existant  pas  en  Tunisie,  pays 
de  protectorat,  I'Etat  a  pu  y  organiser  la  vente  de  la  quinine. 
Un  arrete  du  15  Juin  1909  charge  les  debitants  de  tabac  de 
la  vente  de  la  quinine  dont  ils  s'approvisionnent  a  I'entrepot 
des  Monopoles.  Le  minimum  d'approvisionnement  et  le  prix 
de  vente  sont  reglementes.  II  s'agit  du  chlorhydrate  de  quinine 
en  dragees  de  20  centigrammes. 

Sur  les  lignes  de  chemins  de  fer,  ou  les  mesures  sont  bien 
prises  et  surveillees,  on  constate  I'assainissement  reel  de  gares 
et  maisonnettes  auparavant  fort  paludeennes.  Dans  les  centres 
de  colonisation,  ou  I'intensite  du  paludisme  est  plus  difficile 
a  mesurer  exactement,  on  constate  les  progres  de  I'education  du 
public,  et  une  amelioration  souvent  tres  nette  de  I'etat  paludeen. 

Budget.  —  Le  Budget  officiel  de  I'antipaludisme  monte  a 
quelques  milliers  de  francs  (appointements  et  frais  de  tournee 
du  Directeur  du  service,  achat  de  quinine,  publications  de 
propagande). 

III.  Canipagnes  antipaludiques  en  Corse} — Territoire.  —  La 
Corse  est  une  ile  allongee  du  Nord  au  Sud  sur  200  kilometres  de 
longueur  et  une  largeur  maxima  de  90  kilometres.  Une  chaine 
de  montagnes  dirig^e  selon  le  grand  axe  Nord-Sud  est  separee 

^  Les  renseignements  qui  suivent  m'ont  ete  tres  aimablement  communiquees  par  le 
Dr  Thiers,  president  de  la  Ligue  Corse  contre  le  Paludisme,  que  je  remercie  tres  vive- 
ment  de  sa  grande  obligeance. 


52]  CORSICA  491 

de  la  mer  a  Test  par  une  plaine  longue  de  150  kilometres  et 
large  de  6  a  20  kilometres.  Cette  plaine  orientale  couvre 
190,000  hectares,  pres  du  quart  de  la  superficie  de  I'Tle.  Elle 
est  toute  entiere  infectee  de  paludisme,  a  type  estivo-automnal. 

Population. — Le  Dr  Thiers  estime  a  40,000  le  nombre  des 
habitants  qui  subissent  annuellement  les  atteintes  du 
paludisme  (sur  un  chiffre  total  de  population  qui  n'atteint  pas 
300,000  ames)   pour  le  departement  tout  entier. 

Anophelines. — L'espece  dominante  est  Anopheles  maculipennis 
Meigen. 

Mesures  adoptees.  —  L'Etat  n'a  encore  pris  aucune  mesure 
importante  en  Corse.  Ce  fut  le  Professeur  A,  Laveran  qui,  en 
1901,^  prit  I'initiative  de  conseiller  la  creation  d'une  societe 
locale  pour  I'assainissement  de  ce  pays.  Une  ligue  corse 
contre  le  paludisme  fut  fondee  en  1902  par  le  Dr  Battesti, 
et  depuis  la  mort  de  ce  regrette  savant,  elle  est  presidee  par 
le  Dr  Thiers. 

L'action  des  devoues  Societaires  est  surtout  morale,  elle 
consiste  d'abord  en  une  oeuvre  de  diffusion  dans  le  departement 
de  brochures  de  vulgarisation,  envoi  de  cartes  postales,  pose 
d'affiches  mettant  en  garde  contre  la  piqure  des  moustiques, 
conseils  sur  la  facon  de  prendre  la  quinine,  renseignements  sur 
la  facon  d'organiser  la  production  mecanique,  installation  et 
entretien  de  quelques  maisons  protegees,  destinies  a  servir  de 
modele.^ 

La  Ligue  a  obtenu  des  pharmaciens  que  ses  adherents 
puissent  se  procurer  la  quinine  au  prix  de  quinze  centimes  le 
gramme,  prix  bien  inferieur  aux  prix  en  cours  auparavant. 
Elle  a  decide  la  Compagnie  des  Chemins  de  Fer  departementaux 
d'abord,    les    diverses    Administrations    de    I'Etat    ensuite,   a 

1  Bull.  Ac.  Midecine  :  "  Sur  la  Prophylaxie  du  Paludisme  en  Corse,"  24  Decembre 
1901  ;  et  "  Assainissement  de  la  Corse,"  7  Octobre  1902.  Voir  Battesti:  "Ligue 
Corse  contre  le  Paludisme."  Campagne  1902.  Bastia  1903.  "  La  2eme  Campagne  de 
la  Ligue  Corse  contre  le  Paludisme."     Annee  1903.     Bastia  1903. 

2  Voir  la  communication  des  Drs  Thiers  a  Stefani  au)  Congrh  de  V Alliance 
(£ Hygiene  Sociale.     Lyon,  Mai  1907. 


492       ANTIPALUDIQUES   EN   TERRITOIRE   FRANCAIS    [Sect. 

adopter  les  toiles  metalHques  et  la  prophylaxie  quinique  dans 
les  localites  reputees  paludeennes. 

Resultats  obtenus. — Au  point  de  vue  moral,  I'opinion  publique 
en  Corse  e=t  avertie,  a  I'heure  actuelle,  des  dangers  et  des  causes 
du  paludisme,  ainsi  que  des  moyens  d'y  remedier.  Au  point 
de  vue  pratique  la  morbidite  a  diminue  en  certains  points  bien 
surveilles  :  elle  est  tombee  parfois  de  50%  a  12^,  mais  il  ne 
s'agit  que  des  cas  de  premiere  invasion,  les  recidives  sont  encore 
aussi  nombreuses.  C'est  que  le  zele  des  medecins  qui  dirigent 
la  lutte  antipaludique  et  des  Chefs  d' Administration  n'est  pas 
toujours  seconde  par  la  bonne  volonte  des  interesses  eux- 
memes.  La  question  du  paludisme  devrait  constituer  une  des 
principales  preoccupations  de  la  Commission  gouvernementale 
chargee  actuellement  d'etudier  les  moyens  du  relevement 
economique  de  la  Corse. 

Budget.  —  Les  cotisations  des  Societaires  ont  subventionne 
I'ceuvre  de  la  Ligue  Corse  ainsi  qu'une  somme  de  3,000  francs 
que  lui  attribua  le  Professeur  Laveran  sur  des  fonds  mis  a  sa 
disposition  par  la  caisse  des  recherches  scientifiques. 

IV.  Campagnes  Antipaludiques  dans  les  Colonies  Francaises. — 
Le  Ministere  des  Colonies  a  public  en  1903  des  Instructions 
concernant  les  meswes  a  prendre  contre  les  maladies  endeniiques, 
epidemiques  et  contagieuses.  Mr  le  Medecin  Inspecteur  General 
Kermorgant  y  consacre  22  pages  a  la  hygiene  antipaludique.^ 
II  revient  en  1906  sur  cette  question  dans  un  article  sur  "La 
Prophylaxie  du  Paludisme."  ^  Sur  ses  instructions,  I'etude 
des  Culicides  fut  poursuivie  dans  toutes  les  colonies  Frangaises 
et  montra,  entre  autres  choses,  que  les  seules  colonies  exemptes 
de  paludisme:  la  Nouvelle-Caledonie  et  Tahiti,  sont  en  meme 
temps  indemnes  d'Anophelines.^ 

Mais  on  constate  surtout  des  essais  individuels  de  grillages 
des  habitations.     Et  d'autre  part,  depuis  longtemps,  I'initiative 

^  Voir  Annexe  aux  Annales  cf  Hygiene  et  de  Medecine  Coloniale,  1 903. 
-  Ann.  (T Hyg.  et  Midec.  Colon.,  t.  ix.,  1 906,  pp.  iS-46. 

'  Je  remercie   vivement    Mr    le    Medecin    Inspecteur    General   Kermorgant   des 
renseignements  qu'il  a  bien  voulu  me  communiquer. 


52]  RlfeUNION,   MADAGASCAR  493 

de  prescrire  de  la  quinine  preventive  dans  les  pays  paludeens 
ou  en  expeditions  coloniales  est  laissee  aux  medecins.^ 

Les  renseignements  que  nous  avons  pu  recueillir  parmi  les 
documents  publi6set  au  Ministere  des  Coloniessont  lessuivants: — 

La  Reunion. —  He  de  2,500  kilometres  carres  et  170,000  habi- 
tants infectee  depuis  1867  par  le  paludisme.  Deux  especes 
d'Anophelines :  Myzorhynchus  coustani  et  Pyretophorus  costalis. 

En  1902  le  Colonel  Sordoillet,  commandant  sup6rieur  des 
troupes  edicta  des  reglements,  qui  furent  bien  appliques  dans 
la  population  militaire,  pour  la  quininisation  preventive  et 
curative,  I'emploi  obligatoire  des  moustiquaires  et  la  destruc- 
tion des  moustiques  dans  le  voisinage  des  postes  et  casernes. 

La  mortalite  autrefois  assez  elevee  dans  les  statistiques 
militaires  devient  nulle  en  1904  et  1905,  alors  que  la  mortalite 
dans  la  population  civile  subissait  une  progression  importante. 

Apres  le  depart  de  cet  officier  superieur,  les  mesures  ne 
furent  pas  aussi  bien  surveillees  et  les  atteintes  de  paludisme 
recommencerent.^ 

Madagascar. — Un  decret  du  20  Octobre  1905  autorise  le 
Gouverneur-General  de  Madagascar  a  prendre  par  voie  d'arret^ 
toutes  les  dispositions  necessaires  pour  que  les  sels  de  quinine 
soient  mis  a  la  disposition  de  tous  et  au  plus  bas  prix  possible. 

Le  Professeur  A.  Laveran  fait  emettre  en  1904  un  voeu  par 
I'Academie  de  Medecine  pour  que  les  casernements  militaires 
de  Madagascar  soient  proteges  par  des  toiles  metalliques.' 

Afrique  occidentale  franqaise. — Senegal. — Le  Dr  Thiroux  qui, 
apres  le  Dr  Marchoux  a  specialement  etudie  le  paludisme  du 
Senegal,  rapporte*  les  mesures  prises  pour  assainir  en  1904- 1905 
la  ville  de  Saint-Louis  (20,000  habitants). 

^  Voir  A.  Laveran,  "  Traite  du  Paludisme."    2°  ed.,  1907. 

A.   Billet,    "La   Lutte   contre  la  Malaria  en    France   et   dans    les    Possessions 
Fran^aises  en  1903."     Atti.  de  Soc.  per  gli  Studi  delta  Ma/aria,  t    v.,  1904,  p.  287. 

*  J.  J.  Vassal,   "  Le  Paludisme  a  I'lle  de  la  Reunion."      Atti.  de  Soc.  per  gli 
Studi  delta  Malaria,  t.  viii.,  1907,  p.  19. 

^  Bull.  Acad.  Midec,  "  Seance  du  8  Mars  1904,"  pp.  183-190. 

*  A.  Thiroux  et  L.  d'Anfreville,  "  Le  Paludisme  au  Senegal  pendant  les  Annees 
1905- 1906." 

J.  B.  Bailliere,  1908.  57pp.     PI.  en  couleurs. 


494       ANTIPALUDIQUES   EN   TERRITOIRE   FRANCAIS     [Sect. 

Les  Aiiophelines  du  Senegal  sont : — Pyreiophorus  costalis, 
Myzomyia  funesta,  MyzorJiyyichus  paludis,  Cellia  pharoe^isis, 
Cellia  squamosa. 

On  proceda  au  remblaiement  des  marais  de  la  pointe  nord 
de  la  villa  de  Saint-Louis,  des  marais  du  faubourg  de  Sor. 
Pour  ces  derniers,  on  a  install^  un  systeme  de  drainage,  avec 
siphons  s'ammorcant  d'eux-memes  a  maree  basse  et  ne  fonc- 
tionnant  plus  a  maree  haute.  On  procede  a  des  petrolages 
dans  la  ville  de  Saint-Louis ;  quelques  essais  de  defense 
mecanique  ont  ete  tentes.  La  ligne  du  chemin  de  fer  de 
Saint  -  Louis  a  Dakar  a  toutes  ses  gares  et  ses  logements 
d'employes  proteges  par  des  toiles  metalliques. 

Territoires  des  Rivieres  du  Sud. — Le  Dr  Le  Moal  appliqua 
en  1905  ^  les  mesures  antilarvaires  a  I'assainissement  de  Conakry 
(900  habitants)  batie  sur  I'ile  de  Tumbo,  une  des  villes  les 
plus  paludeennes  d'Afrique.  II  y  organisa  des  brigades  a 
moustiques  qui  eurent  pour  mission  de  remblayer  les  bas- 
fonds,  de  drainer  les  marais,  de  petroler  les  mares. 

Haut-  Senegal  et  Niger.  —  Le  Dr  Boufifard^  conseille,  avec 
examples  a  I'appui,  pour  I'Europeen  la  cure  quinique  preventive 
(dose  quotidienne  de  25  centigrs.  augmentee  en  cas  de  danger 
special)  prolongee  deux  semaine  apres  le  retour  en  pays  sain. 

II  y  joint  I'usage  de  la  moustiquaire  individuelle. 

II  estime  par  contre  la  quininisation  des  indigenes  impossible 
dans  ces  pays  et  croit  les  mesures  antilarvaires  susceptibles 
de  diminuer  le  paludisme  chez  les  Negres.  II  trace  un  pro- 
gramme des  travaux  a  executer  suivant  que  les  agglomerations 
indigenes  sont  en  plaine  ou  en   montagne.     Enfin  I'Adminis- 

^  Le  Moal,  "Campagne  Antipaludique  a  Conakry  en  1905."  Ann.  Hyg.  et 
Mid.   Colon.,  t.  ix.,  1906,  pp.  550. 

Voir  aussi  du  meme  auteur  :  "  Etude  sur  les  Moustiques  en  Afrique  Occidentale 
Fran9aise,  Role  Pathogene-Prophylaxie."     Ibidem,  1906,  pp.  181-219. 

2  Bouffard,  "  Prophylaxie  du  Paludisme  chez  I'Europeen  dans  le  Haut-Senegal 
et  Niger."     Bull.  Soc.  Path.  Exot.,  t.  ii.,  1909,  No.  i,  pp.  34-39. 

"Prophylaxie  du  Paludisme  chez  I'lndigene  dans  le  Haut-Senegal  et  Niger." 
Jbidem,  t.  ii.,  1909,  No.  2,  pp.  84-87. 


52]  INDOCHINA  495 

tration  peut  agir  efficacement  en  choisissant  d'apres  les  regies 
de  I'hygiene  antipaludique  remplacement  des  villages. 

Indochine. — Comme  pour  Madagascar,  un  decret  autorise  le 
Gouverneur  -  General  a  delivrer  aux  indigenes  de  la  quinine 
p-ratuitement  ou  a  tres  bon  marche. 


By   H.   C.   ROSS,   M.R.C.S.,  L.R.C.P. 

Director  of  the  Royal  Southern  Hospital  Researches,  Liverpool 
Lately  in  the  service  of  the  Egyptian  Public  Health  Department 

53.  Mosquito  Reduction  in  Egrypt.— Before  considering  the 
history  and  details  of  the  several  campaigns  started  and  in 
progress  in  Egypt,  it  w^ill  be  better  to  discuss  briefly  the  local 
conditions  which  affect  a  sanitary  measure  of  this  nature. 
Egypt  owes  its  very  existence  to  the  Nile.  Were  it  not  for 
that  river  Egyptian  territory  would  merely  be  a  part  of  the 
desert.  Except  on  the  Mediterranean  Coast  in  the  winter 
months,  rainfall  is  a  negligible  quantity ;  so  that  stagnant  pools 
of  rain-water  like  those  found  in  the  tropics  are  unknown. 
The  only  natural  collections  of  water  in  the  country  are  the 
Nile,  the  two  Bitter  Lakes  through  which  the  Suez  Canal 
passes,  a  fresh -water  lake  —  derived  from  the  Nile — at  the 
Oasis  of  the  Fayoum,  and  two  shallow  sea-water  lakes  near 
the  Mediterranean  Coast.  The  Nile  itself  flows  through  Egypt 
without  receiving  a  single  tributary. 

Although  the  natural  collections  of  water  are  so  few,  Egypt 
may  be  defined  as  a  veritable  marsh  surrounded  by  desert. 
The  marsh  is,  of  course,  confined  to  the  narrow  limits  of  the 
basin  of  the  Nile,  and  the  water  is  the  most  valuable  asset 
of  the  country.  Canals  and  irrigation  channels  are  everywhere, 
and  the  native  spends  his  existence  baling  the  water  either 
out  of  the  Nile  itself,  or  from  the  canals,  or  from  wells,  on  to 
the  soil  itself  In  consequence,  if  there  are  few  natural  collec- 
tions of  water,  the  country  is  riddled  with  puddles  and  artificial 
breeding-places  for  mosquitos. 

The  peculiar  cosmopolitan   nature  of  the  population  must 

496 


Sect.  53]  LOCAL   CONDITIONS  497 

be  mentioned.  The  term  "  native "  refers  to  the  local  subject, 
and  it  is  used  in  contradistinction  to  the  Europeans,  many  of 
whom,  so  far  as  their  instincts  regarding  sanitation  are  con- 
cerned, are  not  very  superior  to  the  native.  Almost  every 
nationality  finds  a  home  in  Egypt,  and  foreign  countries  do 
not  appear  always  to  send  their  best  subjects  when  Egypt  is 
singled  out  as  a  settlement  for  them.  The  native  himself  is 
fairly  easily  led,  especially  the  lower  classes  ;  but  when  he 
becomes  educated,  especially  in  Europe,  he  is  inclined  to  form 
ideas  for  himself  which  are  not  always  of  the  best ;  and  it  is 
then  frequently  necessary  to  do  more  than  to  invite  him  to 
accept  reforms.  The  upper  classes  of  Europeans  are  similar 
to  European  colonists  found  elsewhere  ;  with  this  exception, 
that  they  take  less  patriotic  interest  in  Egyptian  affairs  than 
they  would  if  they  were  living  in  a  colony  of  their  own  country. 
The  low-class  Europeans,  the  low-class  Greeks  or  Italians,  who 
form  a  large  percentage  of  the  population,  are  a  very  difficult 
community  to  deal  with,  and  the  Levantine  may  be  regarded 
as  being  neither  native  nor  low-class  European. 

A  brief  consideration  of  the  Government  of  Egypt  and  the 
laws  in  force  regarding  sanitation  is  necessary.  The  ostensible 
Government  of  Egypt  is  complex.  Egypt  is  Turkish  territory, 
ruled  by  His  Highness,  the  Khedive.  There  is  a  Council  of 
Ministers,  and  the  interests  of  European  subjects  are  safe- 
guarded by  the  Consuls-General  and  Consuls.  Laws  which 
affect  natives  can  be  passed  by  the  Council,  but  important 
measures  which  affect  Europeans  have  to  be  sanctioned  by 
the  country  or  countries  concerned. 

The  British  Agent  has  under  him  several  British  officials 
who  are  supposed  to  act  as  advisers  to  the  native  ministers, 
but  who,  in  reality  and  quite  openly,  have  charge  of  the  several 
Government  Departments.  He  is  practically  the  autocrat  of 
the  country. 

The  only  laws  with  which  we  are  immediately  concerned 
are  those  which  govern  sanitation,  and  they  are  few  in  number. 

2  I 


498  MOSQUITO   REDUCTION    IN   EGYPT  [Sect. 

The  Government  is  under  a  difficulty  with  regard  to  them 
because,  although  they  can  be  enforced  with  the  native,  the 
procedure  with  Europeans  is  more  difficult  owing  to  the 
"  Capitulations."  In  the  event  of  epidemics  of  certain  specified 
diseases,  such  as  plague,  cholera,  etc.,  stringent  measures  can 
be  adopted  with  reference  to  native  individuals  and  habitations. 
In  the  case  of  Europeans,  however,  it  is  necessary  to  invoke 
the  co-operation  of  their  Consuls,  which  involves  delay.  There 
is  a  sort  of  Factories  Act  which  is  applicable  to  natives  and 
Europeans  alike ;  it  necessitates  the  passing  by  the  Government 
of  the  plans  of  new  "  unhealthy  establishments,"  and  it  allows 
existing  ones  to  be  inspected.  Unfortunately,  this  measure 
is  very  elaborate,  not  well  suited  to  the  conditions  found  in 
Egypt,  and  usually  considered  almost  to  be  unworkable  by 
the  inadequate  staff  at  the  disposal  of  the  Director-General 
of  the  Public  Health  Department.  The  native  and  Levantine 
are  so  cunning  that  they  succeed  frequently — and  I  speak  from 
personal  experience — in  evading  this  law  ;  and  the  punish- 
ments, especially  those  given  in  the  mixed  courts  to  Europeans, 
are  so  lenient  that  it  often  pays  the  individual  to  ignore  the 
law  and  suffer  the  small  penalty. 

So  far  as  sanitation  is  concerned,  the  Capitulations  enjoin 
that  no  official  may  enter  the  house  or  property  of  a  European 
subject  unless  he  has  obtained  permission  either  from  the  subject 
himself  or  from  his  Consul.  In  considering  all  sanitary  reforms 
this  has  to  be  taken  into  account ;  the  Consuls  sometimes, 
though  not  often,  are  unwilling  to  assist,  and  officials  in  Egypt 
usually  complain  that  the  Capitulations  obstruct  their  efforts. 
In  fact,  this  has  become  a  tradition,  and  if  any  new  effort  fails, 
the  Capitulations  are  usually  blamed.  There  can  be  no  doubt 
that  the  measure  is  an  obstacle,  though  not  such  a  serious  one 
as  is  made  out,  and  to  this  point  I  shall  again  refer. 

Other  questions  will  be  mentioned  in  the  description  of  the 
several  campaigns,  which  will  now  be  taken  seriatim,  in  the 
order  in  which  they  were  started. 


53]  ISMAILIA  499 

Ismailia. — At  the  present  day  Ismailia  is  a  sleepy  little  town 
picturesquely  situated  on  the  shores  of  Lake  Timsah.  De 
Lesseps  intended  it  to  be  one  of  the  greatest  ports  in  the  world. 
When  the  Suez  Canal  was  opened,  and  the  venture  an  assured 
success,  it  was  determined  to  make  Ismailia  a  model  city,  a 
thriving  port,  and  the  headquarters  of  the  Suez  Canal  Company. 
With  this  end  in  view,  the  Company  acquired  the  control  of  a 
large  piece  of  land  on  the  northern  shore  of  Lake  Timsah,  a 
small  sea-water  lake  through  which  the  Canal  passes,  placed 
in  the  centre  of  the  isthmus  of  Suez,  There  the  offices  of  the 
Company  were  built,  surrounded  by  the  houses  of  its  employees  ; 
and  the  largest  shareholder,  the  Khedive  Ismail  Pasha,  built 
himself  a  magnificent  palace.  Villas  were  erected  overlook- 
ing the  Canal,  and  gardens  were  planned  and  parks  marked 
out.  All  the  ships  in  transit  of  the  Canal  stopped  there,  and 
passengers  were  to  land,  and  cargo  to  Egypt  was  transshipped. 
Then  there  was  boating,  bathing  free  from  sharks,  shooting,  and 
every  inducement  both  for  work  and  play.  Ismailia,  though 
young,  was  very  healthy,  being  situated  in  the  desert  and 
isolated  from  other  towns.  It  was  completely  under  the  con- 
trol of  the  Company,  who  spared  no  expense  to  make  it  a 
model  town  free  from  insanitary  native  huts  or  unsightly 
modern  flats  and  hotels.  The  Government  Offices  of  the 
district  were  situated  there,  with  the  Courts,  and  the  town 
soon  began  to  prosper.  De  Lesseps'  intention  was  on  the 
highroad  to  fulfilment  when,  owing  to  ignorance,  a  false  step 
was  made. 

The  town  was  supplied  with  fresh  water  by  a  shallow  canal 
which  connected  it  with  the  Nile.  The  canal  was  built  in  1877, 
and  replaced  the  old  system  of  transport  of  water  by  camel, 
which  was  in  vogue  during  the  early  years  of  the  Suez  Canal 
construction.  The  water  in  this  canal,  which  was  deepened  in 
1882  to  allow  the  passage  of  canal  boats  trading  between  Cairo 
and  Ismailia,  was  laden  with  a  rich  silt  from  Abyssinia,  and  it 
was  used  to  irrigate  the  desert  and  the  marked-out  parks  and 


500  MOSQUITO    REDUCTION    IN   EGYPT  fSECT. 

gardens,  with  the  result  that  a  veritable  oasis  was  formed. 
Trees  were  planted,  and  the  gardens  grew  apace  under  the 
influence  of  the  irrigation.  But  the  water  was  not  properly- 
controlled,  and  much  of  it  ran  to  waste,  forming  shallow  marshes 
and  ponds  in  and  about  the  town.  With  the  marshes  came 
the  mosquitos  ;  and  with  the  mosquitos  came  the  fever ;  and 
with  the  fever  came  the — downfall.  In  the  days  of  its  salubrity, 
Ismailia  had  progressed  very  rapidly,  rising  to  a  population  of 
10,000 ;  but  when  the  fever  appeared,  all  progress  stopped  and 
decadence  took  its  place.  Nearly  2,000  cases  of  malaria  were 
treated  every  year,  but  probably  many  more  occurred.  Men, 
both  Europeans  and  natives,  were  unable  to  work,  children  were 
always  ill,  the  death-rate  increased,  while  the  birth-rate  fell. 
Every  one  was  down  with  fever,  and  trade  was  soon  at  a  stand- 
still. The  Government  offices  were  closed  and  were  ultimately 
moved  to  Port  Said ;  the  tribunals  were  transferred  to  the 
neighbouring  towns  of  Zagazig  and  Mansurah,  and  the  Suez 
Canal  Company  were,  in  1900,  left  to  face  the  question  whether 
the  town  should  be  abandoned,  or  whether  the  disease  could  be 
prevented. 

In  1877,  when  malaria  first  appeared  in  Ismailia,  300  cases 
occurred  from  August  to  December.  The  next  year  there  were 
400  cases ;  and  the  annual  sick-rate  remained  at  about  this 
figure  until  1885.  The  disease  then  became  worse,  and  in  1891 
nearly  2,500  cases  were  recorded.  Acting  on  the  old  assumption 
that  the  disease  is  caused  by  a  miasm,  the  Canal  Company 
made  several  efforts  to  combat  it  by  partially  draining  the 
marshes,  and  probably  these  efforts  prevented  the  epidemic 
reaching  extreme  dimensions.  The  discovery  of  the  trans- 
mission of  malaria  by  mosquitos  was  not  completed  until  1899. 
In  1902  the  Company  resolved  to  take  further  advice.  They 
sent  a  medical  officer  to  Italy  to  make  enquiries  about  the 
anti-mosquito  measures  being  conducted  there,  and  then  they 
invited  my  brother.  Major  Ross,  to  go  to  Ismailia  to  advise 
them.     He  arrived  at  the  Suez  Canal  on  12th  September  1902, 


53]  ISMAILIA  501 

in    company  with    Sir   William    MacGregor,   the   Governor   of 
Lagos,  who  wished  to  study  the  malaria  at  Ismailia  with  him. 
The  first  measure  to  be  recommended  by  Major  Ross  was 
the   extermination   of  mosquitos,  which  was   immediately   put 
into   effect,   the    Company   bearing   the   entire   expense.      The 
main   breeding-places  for  mosquitos  were  found  to  be  shallow 
irrigation  pools  and  puddles  in  the  gardens  and  yards,  where 
Anopheline  larvae  were  taken.     Each    house  has  its  cesspool, 
according  to  the  general  rule  in  Egypt,  for  there  are  no  properly 
instituted  sewerage  arrangements  in  the  country,  and  all  sewage 
passes  directly  into  the  "fosse"  under  the  house.    The  fresh-water 
canal,  which  brings  drinking  -  water  from  the  Nile  and  which 
passes  through  the  town,  does  not  harbour  mosquitos.     There 
the  water  is  running,  and  fish  are  plentiful ;  but  a  short  distance 
away  from  the  town  a  marsh  was  formed  by  leakage  from  the 
canal,  and    here  larvae  were  found.     Rigorous    measures  were 
adopted ;  the  marsh  was  drained  and  the  pools  were  filled  up. 
A  mosquito  brigade  was  formed,  which  consisted  of  a  European 
foreman  and  two  natives.     Their  duty  was  to  visit  every  house 
once  a  week,  and  to  treat  the  cesspools  with  petroleum.     Irriga- 
tion canals  and  channels  were  cleared  of  reeds,  and  the  water 
made  to  flow  swiftly.     When  a  certain  garden  had  received  its 
proper  supply  of  water,  the  flow  was  stopped  and  the  water 
allowed    to    soak    in.      All    the    work    was   systematic;    each 
breeding-place   was   visited    and    treated   on    a  certain   day  in 
each  week,  which  was  kept  up  throughout  the  year.     Similarly, 
all    water   vessels,   tubs,   and    flower   vases   were   emptied.     A 
penalty  was  imposed  on  the  inhabitants  if  they  did  not  report 
untreated  collections  of  water  to  the  authorities.     No  expense 
was  spared  to  make  the  new  sanitary  measure  a  success. 

There  is  one  difference  between  the  Ismailia  campaign  and 
the  others  which  must  be  mentioned.  The  Capitulations  did  not 
form  an  obstacle  there.  The  laws  at  Ismailia  were  the  same 
as  those  elsewhere,  but  the  Canal  Company  made  short  work 
of  the  Capitulations,  for  practically  all  the  inhabitants,  whether 


502  MOSQUITO   REDUCTION   IN   EGYPT  [Sect. 

European  or  native,  were  employees  of,  or  dependent  on  the 
Company,  and  if  they  objected  to  the  visits  of  the  brigade, 
they  could  be  either  dismissed  or  have  their  salaries  cut. 

Instituted  by  their  President,  Prince  d'Arenberg,  the  Suez 
Canal  Company  can  well  be  proud  of  the  result  of  the  anti- 
mosquito  work  at  Ismailia.     Last  year  not  a  single  new  case 
of  malaria  occurred  there,  and  the  disease  has  been  stamped  out. 
Ismailia  affords  a  striking  example  of  the  great  commercial 
importance  of  malaria  prevention.     When  De  Lesseps  decided 
that  the  headquarters  of  the  Canal  should  be  at  Ismailia,  he,  of 
course,  did  not  appreciate  the  possibility  of  invasion  by  malaria, 
I  believe  that  his  decision  was  due  to  the  presence  of  the  large 
natural  harbour  afforded  by  Lake  Timsah,  where  a  fleet  of  ships 
could   anchor   to   take   in    coal    and    provisions   on   their   way 
through  the  Canal,  without  obstructing  the  transit  of  other  ships. 
It  is  true  that  all  coal  has  to  be    imported  from  Europe,  but 
in  spite  of  the  fact  that  Ismailia  is  nearly  50  miles  from  the 
Mediterranean,  the  presence  of  the  natural  harbour  there  was 
so  important,  that  the  extra  expense  which  would  have  to  be 
incurred  in  bringing  the  coal  through  the  50  miles  of  canal  was 
hardly  taken   into   consideration.      In    fact   it  paid  the  Canal 
Company  to  insist  on  all  coal  being  brought  to  Ismailia,  because 
dues  were  obtained  for  its  transit.     Commercially,  everything 
was  in  favour  of  Ismailia  being  made  the  headquarters  of  the 
Canal.     The  point  is  an  interesting  one,  for  De  Lesseps'  great 
commercial  proposal  was   disposed  of  by  malaria.     For  years 
the  Company  tried  to  force  ships  to  coal  and  land  passengers 
at  the  fever-stricken  town,  but  now  they  have  been  compelled 
to  relinquish  the  natural  harbour,  and  to  build  an  artificial  one 
at  Port  Said  (which  requires,  and  always  will  require,  incessant 
dredging)  at  an  outlay  of  many  millions.     Even  natural  assets 
of  enormous   commercial   value,  such   as   this  harbour  in  the 
greatest  shipping  highway  of  the  world,  fail  utterly  in  the  face 
of  a  comparatively  small  epidemic  of  malaria.     The  artificial 
harbour  at  Port  Said  has  been  built,  and  Ismailia  has  dwindled 


53] 


ISMAILIA 


503 


into   insignificance,   at   a    cost    which    probably   can    never   be 
estimated. 

The  results  of  the  anti-malaria  work  are  well  known. 
Accurate  figures,  showing  the  number  of  severe  cases  of  malaria 
which  had  occurred  before  the  mosquito  work  was  started,  had 
been  kept,  and  these  could  be  compared  with  those  obtained 
afterwards.  Every  employee  of  the  Company  is  obliged  to  go  to 
a  doctor  when  ill  in  order  to  obtain  a  certificate  of  absence,  so 
that  all  cases  were  easily  recorded.  But  there  must  have  been 
a  number  of  cases  of  early  and  slight  fever,  in  which  the  malaria 
parasite  would  not  be  in  evidence,  and  which  would  not 
necessitate  the  patient  lying  up  ;  and  besides,  there  were  those 
cases  which  occurred  in  persons  who  were  not  employed  by 
the  Company,  and  also  many  native  women  and  children,  who 
will  not  go  to  doctors.  But  the  results  which  are  given  by 
Dr  Pressat  are  very  interesting. 


Years. 

Cases. 

Years. 

Cases. 

Years. 

Cases. 

1877 

300 

1888 

1,400 

1899 

1,545 

1878 

4CK) 

1889 

1,450 

1900 

2,284 

1879 

500 

1890 

1,900 

1901 

1,990 

1880 

4CX3 

1891 

2,590 

1902 

1,551 

1881 

450 

1892 

2,050 

1903 

214 

1882 

480 

1893 

1,750 

1904 

90 

1883 

550 

1    1894 

1,100 

1905 

37 

1884 

9CX3 

1895 

1,350 

1906 

No  fresh  cases. 

1885 

2,000 

1896 

1,150 

1907 

No  fresh  cases. 

1886 

2,300 

i    1897 

2,089 

1908 

No  malaria  contracted  in 

Ismailia. 

1887 

1,800 

;  1898 

1 

1,545 

And  now,  although  cases  of  malaria  are  occasionally  intro- 
duced into  the  town  from  the  villages  situated  higher  up  the 
fresh-water  canal,  such  as  Mahsammah,  Nefiche,  and  Tel  el 
Kebir,  yet  the  disease  never  spreads  there  because  the  Ano- 
phelines  are  absent,  and  there  is  no  longer  any  necessity  for 
taking  quinine. 

The  chief  difficulty  and  source  of  expense  at  Ismailia  was 
that  of  the  initial  control  of  the  irrigation,  and  the  drainage  and 


S04  MOSQUITO   REDUCTION   IN   EGYPT  [Sect. 

filling  up  of  the  marshes  which  surrounded  the  town.  And 
even  now,  in  the  autumn,  mosquitos  find  their  way  there  from 
marshes  situated  to  the  west  above  the  town,  there  being  no 
habitations  between.  These  marshes  would  cost  much  to  drain 
or  fill — an  unnecessary  expense.  The  number  of  mosquitos  in- 
troduced into  the  town  from  this  source  is  so  small  that  it  may 
well  be  ignored,  and  there  is  but  little  chance  of  their  becoming 
infected,  as  there  are  now  no  cases  of  fever  in  the  town. 

The  cost  of  the  permanent  works,  including  the  filling  up 
with  sand  and  the  drainage  of  the  marshes,  pools,  and  the 
control  of  the  irrigation,  was  50,000  francs  (;^2,ooo). 

The  annual  cost  of  the  regular  work  of  clearing  streams, 
ponds,  and  of  keeping  the  gardens  clear  of  mosquito  larvae  is 
7,800  francs.  And  the  oiling  of  the  cesspools  and  the  general 
work  of  the  mosquito  brigade  is  10,500  francs.  Of  this  sum, 
5,300  francs  are  spent  annually  on  oil,  and  5,2CO  francs  on 
salaries  and  other  incidental  expenses.  Thus  the  cost  of  the 
regular  annual  work  is  now  i  franc  90  centimes  per  head  of 
population  per  year  ;  at  first  it  was  2  francs  30  centimes.  The 
total  annual  cost  is  now  about  ;i^i,ooo  per  year.  And  for  this 
sum,  after  an  original  outlay  of  iJ^2,ooo,  Ismailia  is  kept  healthy 
and  free  from  fever. 

But  the  work  must  always  be  kept  up,  though  the  cost  of  it 
will  gradually  decrease.  As  in  Port  Said,  if  the  mosquito 
brigade  stops  work  for  a  week,  the  mosquitos  return.  The 
men  require  constant  supervision.  M.  Doyen,  of  the  Suez  Canal 
Company,  is  to  be  heartily  congratulated  on  the  way  the  work 
progresses,  for  the  town  continues  free  from  malaria. 

But  Ismailia  has  never  recovered  the  blow  that  malaria  dealt 
it,  for  natives  now  call  it  "  El  turba  e'nadeefa  "  (the  clean  tomb). 

Port  Said. — Port  Said  was  a  much  more  difficult  problem 
than  Ismailia.  The  town  is  larger,  with  a  very  cosmopolitan 
population  of  50,000  inhabitants.  It  is  built  on  a  triangular 
spit  of  land  bordered  by  the  Mediterranean,  the  Suez  Canal, 
and  the  shallow  sea-water    lake   of   Menzalah.      The  price  of 


53]  PORT   SAID  505 

land  is  considerable,  as  the  town  cannot  expand,  with  the  result 
that  high  buildings  containing  residential  flats  are  being  erected 
everywhere.  The  soil  consists  of  sand,  and  the  subsoil  water, 
which  is  really  sea-water,  can  be  found  at  a  depth  of  about  a 
metre.     Port  Said  may  be  said  to  be  built  on  a  sand-bank. 

All  the  drainage  from  the  houses  passes  into  cesspools 
usually  placed  under  the  floor.  Owing  to  the  height  of  the 
subsoil  water,  these  cesspools  are  frequently  too  small  to  be 
adequate,  and  overflow  as  a  common  result.  They  are  con- 
tinually being  emptied  at  great  expense,  which  falls  on  the 
landlords,  who  are  not  too  willing  to  carry  out  this  duty.  It 
may  be  imagined,  therefore,  that  before  the  mosquito  campaign 
was  started,  that  is,  before  any  proper  systematic  sanitary 
administration  was  instituted,  Port  Said  was  one  of  the  most 
insanitary  places.  Many  of  the  houses  had  basements,  and  the 
cesspools  were  bricked  reservoirs  built  in  among  the  rooms 
contained  in  them.  When  the  cesspools  became  full,  they 
frequently  burst,  and  the  sewage  passed  into  the  rooms  which 
formed  the  basement.  I  have  often  seen  shops  and  dwellings 
with  only  a  wooden  flooring  separating  the  living  rooms  from 
the  sewage,  and  more  than  occasionally  one  used  to  see  persons 
living  in  a  room  with  the  sewage  oozing  up  through  the  floor. 
Without  exaggeration,  one  can  say  that  a  few  years  ago  Port 
Said  was  famed  for  being  one  of  the  most  disgusting  "  holes  " 
on  the  face  of  the  earth.  Crime  was  rife,  every  one  looked  ill, 
and  it  was  openly  said  that  all  the  scoundrels  in  the  world 
collected  there.  In  fact,  little  more  than  ten  years  ago  it  was 
hardly  safe  to  walk  in  the  streets  at  night.  The  population  is 
largely  European,  to  a  far  greater  proportion  than  in  most 
other  Egyptian  cities  ;  and  owing  to  the  Capitulations,  the 
Government  police  officials  could  not  enter  the  European 
houses,  and  knew  little  of  what  was  going  on. 

But  the  filth  and  general  insanitation  were  almost  inde- 
scribable. Sewage  used  frequently  to  be  seen  trickling  down 
the  pavements  from  the  overflowing  cesspools,  and  puddles  of 


5o6  MOSQUITO   REDUCTION    IN    EGYPT  [Sect. 

faecal  matter  formed  in  the  roads.  Sometimes  the  stench  was 
such  that  certain  houses  and  corners  were  deliberately  avoided 
by  pedestrians.  Mosquitos  bred  in  the  sewage  and  then  bit  the 
inhabitants.  The  authorities  could  do  little  or  nothing  owing 
to  the  Capitulations  (so  they  said).  Consuls  would  be  approached 
by  means  of  endless  correspondence  and  red  tape.  Sometimes 
a  little  improvement  was  effected,  but  usually  nothing  was  done. 
Fever  was  rife  and  mortality  very  high.  It  was  dangerous  then, 
as  in  Cairo  now,  to  keep  a  European  child  in  Port  Said  during 
the  summer  months.  I  have  seen  an  infant's  face  so  covered 
with  mosquito  bites,  that  I  thought  it  was  suffering  from 
confluent  small-pox.  The  whole  place  was  a  "  sink  of  iniquity," 
a  statement  which,  I  think,  will  be  confirmed  by  any  person 
who  passed  through  the  Suez  Canal  a  few  years  ago. 

But  the  mosquito  campaign  has  changed  all  that.  Practically 
speaking,  the  Capitulations  have  vanished.  Sanitary  inspectors, 
on  the  plea  of  mosquito  destruction,  now  enter  every  house, 
and  every  dwelling-room  if  necessary,  in  the  town.  Everything 
is  known  and  reported  to  the  police  should  occasion  require  it. 
And  the  remarkable  thing  is  that  no  one  appreciates  this  reform 
more  than  the  Europeans  themselves,  even  the  lowest  class 
Levantine.  Children  are  healthy,  trade  has  increased,  and 
crime  and  vice  have  been  reduced  to  a  minimum.  In  fact,  Port 
Said  now  resembles  a  quiet  seaside  watering-place. 

The  history  of  the  reform — and  it  is  well  worth  recording — 
is  a  remarkable  one.  Towards  the  end  of  1905  my  brother, 
E.  H.  Ross,  then  a  surgeon  in  the  British  Navy,  was  appointed 
Medical  Officer  of  Health  to  the  town  by  Sir  Horace  Pinching, 
the  Director-General  of  the  Public  Health  Department.  The 
new  officer,  appreciating  the  results  obtained  at  Ismailia,  owing 
to  the  advice  of  our  brother,  R.  Ross,  saw  that  similar  measures 
would  effect  far  greater  results  at  Port  Said.  It  was  true 
that  there  was  no  epidemic  of  malaria  as  at  Ismailia,  but 
Anophelines  had  been  found  in  many  places,  and  malaria  did 
undoubtedly  occur.      Cellia  pharoensis   and    Anopheles   ptaculi' 


53]  PORT  SAID  507 

pennis,  both  malaria-propagating  mosquitos,  were  found  breed- 
ing in  puddles  and  cesspools.  Moreover,  the  ubiquitous  Culex 
fatigans  and  Stegomyia  fasciata  were  a  positive  nuisance. 
Every  one  was  bitten  day  and  night.  The  cesspools  were  full 
of  larvae.     E.  H.  Ross  reported  as  follows  : — 

"  In  Port  Said,  only  those  who  lived  in  the  town  before  1906 
can  realise  the  misery  caused  by  this  pest.  Quite  apart  from 
the  fever,  the  constant  irritation  of  the  mosquito  bites,  and  the 
persistent  manner  with  which  the  insects  used  to  attack  one, 
both  during  the  day  and  night,  nearly  drove  one  mad.  I  have 
seen  clerks  in  offices  arranging  mosquito-nets  over  their  desks 
in  the  daytime,  hanging  them  on  to  the  gas  brackets,  and  the 
native  workmen  in  laundries  covering  their  naked  feet  and  legs 
in  paper  to  prevent  themselves  being  bitten.  A  certain  amount 
of  immunity  against  the  irritation  is  produced  in  time,  and 
certain  individuals  feel  the  effects  of  the  venom  less  than  others, 
but  they  are  bitten  for  all  that.  Then  the  heat  of  the  mosquito- 
net  at  night.  Every  time  one  moved  in  one's  sleep,  and  threw 
off  any  bed-clothes  that  the  heat  would  allow,  one  was  liable 
to  touch  the  net  with  a  hand,  arm  or  leg,  and  to  be  bitten 
through  the  net.  And  the  persistent  scratching  and  the  dis- 
turbed sleep — these  things  have  to  be  experienced  to  be  realised. 
I  have  estimated  that  a  mosquito-net  makes  a  difference  of 
three  degrees  Fahrenheit  when  there  is  any  wind,  for  it  keeps 
out  any  air  that  there  is.  How  well  I  remember  the  many 
evenings  sitting  at  the  laboratory  table,  trying  to  dissect 
mosquitos,  trying  to  investigate  their  interior  economy,  while 
they  in  their  turn  were  doing  their  utmost  to  investigate  me, 
nibbling  my  ankles,  raising  wheals  on  my  wrists  and  neck,  and 
making  all  work  impossible.  At  all  events  I  think  that  they 
had  the  best  of  the  bargain.  And  then,  how  often  in  a  fit  of 
rage  one  has  chased  them  with  a  fly-wisk,  or  stalked  them  with 
a  candle,  making  oneself  hot  with  the  exertion  of  numberless 
futile  attempts,  until  driven  to  bed  and  the  refuge  of  the 
mosquito-net,  hot  and  in  a  bad  temper." 

It  was  clear  that,  in  spite  of  the  possibility  of  there  not 
being  very  much  malaria  at  Port  Said,  the  general  prevalence 
of  mosquitos  probably  caused  illness,  and  my  brother  grasped 
that  an  attempt  at  their  destruction  could  only  bring  good 
results  and  might  lead  to  the  general  cleaning  up  of  the  town. 


5o8  MOSQUITO   REDUCTION   IN   EGYPT  [Sect. 

He  therefore  made  enquiries  as  to  how  much  fever  there  was 
which  could  be  attributed  to  mosquitos.  Formerly,  a  fever  of 
mild  type,  which  used  to  affect  whole  households  and  which 
lasted  for  two  or  three  days,  was  common  in  Port  Said ;  some- 
times it  was  called  dengue  and  sometimes  influenza.  Quinine 
was  beneficial  in  some  cases.  Malaria  did  occur,  a  fact  which 
was  proved  by  Dr  Cufifey,  the  Medical  Officer  of  the  English 
Hospital.  Anophelines  were  sought  for  and  found,  but  not  in 
very  great  numbers,  although  they  were  breeding  in  many  parts 
of  the  town.  An  examination  of  480  children  showed  that  162 
were  suffering  from  anaemia  and  splenic  enlargement,  and,  out 
of  136  children  examined  in  the  hospital  wards,  10  were  found 
with  malarial  cachexia. 

Dengue  was  also  prevalent,  and  came  in  epidemics  from 
other  parts  of  Egypt.  This  disease  is  said  to  be  conveyed  by 
Culex  fatigans,  which  is  a  very  common  mosquito  throughout 
Egypt.  Then  there  was  the  disease  known  as  Simple  Con- 
tinued Fever,  which  seems  to  infect  schools  and  factories. 

Unfortunately,  there  were  no  reliable  statistics.  Diseases 
are  supposed  to  be  notified  in  Egypt,  but  doctors  do  not  obey 
the  regulation,  which  is  not  properly  enforced.  Natives  do  not 
usually  consult  doctors,  and  patients  are  frequently  not  seen 
until  death.  The  Public  Health  Department  thinks  that  a 
cursory  examination  of  a  dead  body,  with  a  rough  speculation 
of  the  disease  from  which  the  person  suffered,  is  sufficient  to 
form  an  idea  of  the  diseases  prevalent  in  Egypt.  Statistics  are 
published,  but  they  are  quite  worthless ;  the  only  reliable  data, 
therefore,  are  the  number  of  registered  deaths.  In  1904  the 
number  was  1,450;  in  1905,  1,208  ;  in  1906,  1,199;  and  in  1907, 
1,412.  The  actual  population  was  unknown,  and  although  a 
census  has  been  taken  recently,  it  is  not  accurate.  The  absence 
of  reliable  figures  is  the  most  unsatisfactory  part  of  anti- 
mosquito  work  in  Egypt,  except  at  Ismailia. 

As  in  subsequent  campaigns,  two  steps  were  necessary  at 
the  outset :  to  estimate  the  cost  and  obtain  the  necessary  funds, 


53]  PORT   SAID  ^6g 

and  to  arrange  a  scheme  to  overcome  the  Capitulations.  To 
estimate  the  cost  a  house-to-house  examination  was  made.  At 
first  it  was  decided  to  treat  only  the  European  quarter,  which 
lies  to  the  east  of,  and  is  distinct  from,  the  native  quarter. 
The  European  quarter  was  chosen  because  it  contained  more 
mosquitos ;  and  if  the  work  there  was  successful  it  would  be  a 
good  example  to  the  natives  who,  especially  the  Mahomedans, 
are  suspicious  of  innovations.  Moreover,  this  was  the  first 
campaign  in  which  the  Capitulations  formed  a  difficulty,  and 
the  starting  of  the  campaign  in  the  European  quarter  formed 
an  experiment  which  demonstrated  how  effectually  that 
difficulty  could  be  overcome.  I  wish  to  lay  stress  upon  this 
point,  for  the  Capitulations  in  Egypt  have  defied  the  greatest 
administrators,  yet  a  junior  official  in  the  Egyptian  Public 
Health  Department  succeeded,  by  instituting  the  mosquito 
campaign  at  Port  Said,  in  showing  how  easily  this  obstacle  to 
reform  can  be  overcome.     My  brother  reports  as  follows : — 

"Beginning  at  the  easternmost  end,  namely,  at  the  street 
bordering  the  canal,  every  house  and  garden  in  the  European 
quarter  was  visited  seriatim.  Street  by  street  the  examination 
was  made,  and  the  number  of  permanent  water  collections,  such 
as  cesspools,  flooded  cellars,  fountains,  water  tubs,  counted, 
with  a  note  as  to  the  number  of  square  metres  water  surface 
they  contained.  The  number  of  days  required  to  make  this 
examination  from  east  to  west  and  from  north  to  south  by  one 
person  was  also  noted,  and  then  an  allowance  of  half  a  litre 
of  mixed  equal  parts  of  crude  and  refined  petroleum  allowed  for 
each  square  metre  of  water  surface  per  week.  This  gave  the 
amount  of  oil  required  to  destroy  the  mosquito  larvae  in  all  the 
water  in  the  town  every  week,  and  the  estimate  was  therefore 
multiplied  by  fifty-two,  as  the  work  has  to  be  repeated  every 
week  during  the  year,  some  mosquitos  breeding  during  the 
winter  as  well  as  during  the  summer  months.  Then  by  a  simple 
calculation  it  was  determined  that  it  would  require  a  gang  of 
workmen,  containing  five  men  under  the  charge  of  a  foreman, 
to  apply  the  oil  to  all  permanent  collections  of  water  in  the 
European  quarter  every  week ;  and  therefore  one  mosquito 
brigade  would  be  required  to  get  rid  of  the  mosquitos  in  this 
part  of  the  town.     The  price  of  oil  in  Port  Said  is  as  follows  : — 


5IO  MOSQUITO   REDUCTION    IN   EGYPT  [Sect. 

crude  oil  in  tins  containing  i8  litres  (4  gallons)  is  8  piastres 
per  tin,  and  refined  oil  is  1 1  piastres  per  tin.  To  the  cost  of 
the  amount  of  oil  required  per  year,  then,  it  was  necessary  to 
add  the  yearly  wages  of  the  five  workmen  at  6  piastres  per  day 
each  (is.  3d.),  and  the  foreman  at  L.E.  5  per  month.  The 
purchase  of  an  oil  barrel  on  wheels,  five  buckets,  five  half-litre 
tin  measures,  overalls  for  each  workman,  and  allowing  for  small 
repairs  to  the  equipment,  etc.,  the  estimate  of  the  cost  of  the 
campaign  in  the  European  quarter  was  obtained  per  year.  The 
estimate  amounted  to  L.E.  800,  but  the  actual  cost  for  the  first 
year  was  L.E.  719  (L.E.  =  about  21  shillings). 

"  The  estimate  had  been  made  and  the  money  subscribed, 
and  it  remained  only  to  obtain  the  necessary  official  permission 
to  enter  the  houses  of  all  foreign  subjects  from  the  various 
consuls,  so  that  the  work  would  not  be  hindered  by  the  domicile 
clause  of  the  Capitulations.  In  order  to  obtain  this  permission, 
we  advertised  in  every  direction,  spoke  to  all  influential  persons 
and  made  people  interested,  and  then  when  the  Governor  wrote 
officially  to  all  the  consuls,  they  unanimously  consented  to  assist 
us  in  every  way,  and  gave  the  sanitary  authority  of  the  town 
permission  to  enter  the  houses  of  their  subjects  for  the  purpose 
of  '  disinfection  and  for  killing  mosquitos ' ;  and  each  consul 
appointed  a  prominent  member  of  his  community,  to  whom  any 
difficulty  could  be  referred  without  officially  disturbing  the 
consulate  concerned.  We,  on  our  part,  undertook  to  supervise 
the  work  carefully,  as  the  workmen  had  to  enter  every  house 
once  every  week,  and  to  take  all  reasonable  precautions  to 
ensure  their  honesty.  And  in  this  respect  it  is  noteworthy 
that  although  the  work  has  now  been  in  progress  without 
interruption  for  three  years,  there  has  not  been  a  single  charge 
of  dishonesty  upheld  against  the  workmen,  nor  has  there  ever 
been  occasion  to  appeal  to  the  consular  delegates. 

"  The  preliminaries  had  taken  two  months,  but  everything 
was  ready  for  a  start  early  in  May  1906.  Many  good  authorities 
had  said  that  it  would  be  found  impossible  to  clear  the  town, 
or  a  portion  of  it,  of  the  mosquitos  which  infested  it  ;  even 
as  they  say  that  it  will  be  impossible  to  clear  Cairo  to-day. 
But  it  was  determined  to  try.  A  gang  of  five  men  were  engaged. 
They  were  all  natives  of  good  character  who  lived  in  and 
had  families  in  the  town.  A  Greek  foreman  was  found  who 
could  speak  all  the  necessary  languages,  which  include  Arabic, 
English,  French,  Italian,  Greek  and  Turkish.  An  iron  barrel, 
capable  of  holding  300  litres,  fitted  to  wheels  to  enable  it  to 
be  pushed  about  the  streets,  was  bought,  and  each  workman 
was  given  a  bucket,  a  half-litre  measure,  and  a  broom-stick, 


53]  PORT   SAID  5" 

while  the  foreman  was  armed  with  a  note-book.  This  was  the 
equipment  for  the  European  quarter ;  and  the  following  routine 
was  instituted.  The  quarter  was  subdivided  into  six  equal 
portions,  one  for  each  week-day.  Work  begins  every  Monday 
morning  at  the  Governor's  house,  and  one  member  of  the 
brigade  visits  every  house  allotted  to  him  that  day.  Every 
house  is  numbered,  and  is  placed  in  the  charge  of  one  work- 
man, who  is  responsible  for  the  mosquitos,  or  the  absence  of 
them,  in  that  house.  On  Tuesday  morning  at  seven  o'clock 
the  brigade  begins  where  it  left  off  on  the  Monday  evening  ; 
and  so  on,  until  the  whole  of  this  part  of  the  town  is  com- 
pleted by  Saturday  night  at  the  Governor's  house  again.  Thus 
every  house  in  the  quarter  is  visited  by  the  same  workmen  at 
the  same  hour  of  the  same  day  every  week,  and  the  tenants 
know  when  to  expect  him,  and  can  complain  to  the  foreman  if 
he  doesn't  come  regularly.  Each  workman  fills  his  bucket  with 
mixed  crude  and  refined  oil  from  the  oil  -  cart  in  the  street. 
When  he  arrives  at  the  house  allotted  to  him  he  asks  the 
tenants  if  they  have  been  annoyed  by  mosquitos  during  the 
week.  If  the  answer  is  in  the  negative,  he  enters  the  house 
with  their  permission,  and  pours  a  small  quantity  of  oil  down 
each  water-closet  and  sink.  He  mounts  to  the  roof,  where 
in  Port  Said  the  wash-houses  are  usually  situated,  and  empties 
out  all  tubs  and  basins  containing  water.  He  examines  the 
kitchens  and  servants'  rooms  in  each  flat,  for  any  collection 
of  water  which  they  may  contain.  Householders  are  now  quite 
used  to  this  weekly  visit,  for  the  men  are  well  known,  and  it 
serves  to  remind  the  tenants  to  see  that  the  workman  carries  out 
his  duties  properly  ;  and  at  the  same  time  they  are  advised  to 
empty  out  all  water  in  which  mosquitos  are  likely  to  breed,  as 
in  flower-vases  and  in  suchlike  utensils.  The  workman  then 
descends  to  the  basement,  where  he  examines  carefully  every  cellar 
for  any  water  or  sewage,  and  he  then  opens  the  cesspool  of  the 
building  and  pours  into  it  that  amount  of  oil,  allowing  now,  after 
three  years,  a  quarter  of  a  litre  for  each  square  metre  of  water 
surface  it  contains,  as  nearly  as  possible.  The  oil  on  the  surface 
of  the  cesspool  water  is  then  well  stirred  with  the  broom-stick, 
so  that  it  may  spread  everywhere  evenly.  Lastly,  he  visits  the 
garden  and  examines  the  fountain  and  the  water-taps,  flower- 
pots, and  the  yard  if  there  is  one  ;  and  then,  when  finished,  he 
goes  on  to  the  next  house  allotted  to  him,  repeating  the  process 
while  refilling  his  bucket  from  the  oil-cart  in  the  street.^ 

^  In  Port  Said,  mosquitos  do  not  breed  in  the  drinking-water  cisterns,  as  the 
filtered  water  contains  no  food  for  the  larvae.  We  have  therefore  been  able  to 
ignore  house  cisterns. 


512  MOSQUITO   REDUCTION    IN    EGYPT  [Sect. 

"  But  should  the  tenants  complain  of  the  presence  of  mosquitos, 
and  the  workman  find  that  the  cesspool  is  full,  or  that  the 
cellars  contain  water,  he  at  once  informs  the  foreman,  and  they 
both  begin  a  careful  search  for  the  mosquito  larvae.  The 
foreman  reports  at  the  Public  Health  Office  every  morning  at 
noon,  and  details  the  presence  of  mosquitos,  and  whether  the 
larvae  have  been  found  or  not.  He  also  reports  on  the  sanitary 
condition  of  the  streets  dealt  with,  and  the  houses  examined 
that  day,  and  states  whether  any  cesspool  requires  pumping 
out,  or  whether  any  cellar  has  water  in  it,  in  which  case  the 
proprietor  of  the  house  is  dealt  with  by  the  Sanitary  Inspector, 
and  an  extra  foreman  is  sent  down  to  find  the  mosquito  larvae, 
when  they  cannot  be  found  by  the  brigade. 

"  Ultimately,  when  the  mosquito  larvae  have  been  found — 
and  they  can  always  be   discovered   if  carefully  sought  after, 
either  in  the  house  itself  or  on  the  premises — some  are  put  into 
a  bottle  and  examined.     If  there  are  any  nymphs,  it  is  known 
that  the  eggs  have  been  laid   for  more  than  seven  days,  and 
therefore  the  workman  responsible  for  the  house  has  neglected 
to  oil  the  water  in  which  they  were  found,  and  he  is  punished. 
But  more  often  it  is  found  that  the  proprietor  of  the  house  is 
at  fault,  and  the   mosquitos  have  reappeared  because  he  has 
neglected    to    have  the  cesspool    pumped  out ;   and    in    con- 
sequence of  its  being  full  it  has  overflowed  or  has  burst,  and 
the  sewage  has  collected  in  the  cellars,  and  there  the  mosquitos 
were  breeding.     In  this  case  the  proprietor  is  written  to  and  is 
warned    to  empty  the   cesspool  without  delay,  or  he  will  be 
sued  and  fined  in  the  Courts  ;  for  there  is  a  law  which  enables 
us  to  do  this.     Every  cesspool  in  the  town  has  been  fitted  with 
a  movable  iron    door,  so  that  access  can   be  obtained  to   its 
interior  when  desired.     We  persuaded  the  proprietors  of  all  the 
houses  to  put  these  in,  for  we  found  that  there  are  some  cess- 
pools into  the  farthest  corners  of  which  the  oil  cannot  reach 
when  poured  in  through  the  water-closets  and  sinks,  or  even 
through  the  door.     This  is  probably  due  to  solid  sewage  float- 
ing on  the  surface  of  the  water  and  preventing  the  oil  spreading 
evenly.     In  such  places  the  oil  is  well  stirred  with  a  broom- 
stick to  make  it  reach  all  parts  ;  but  if  this  fails  also,  then  we 
have  had   recourse  to  the  automatic   oilers   described    in    the 
Annals  of   Tropical  Medicine   for  June    1907,    and    they   have 
been  most  successful  for  the  purpose,  though  even  when  these 
are  in    use   the  cesspools   containing  them   must   be  carefully 
examined  every  week  in  case  the  oiler  becomes  clogged.     This 
is  recognised  by  the  presence  of  male  and  female  mosquitos 
in  the  cesspool  after  ten  days  have  passed  since  the  clogging. 


S3]  PORT  SAID  513 

"  This  is  the  routine  which  has  been  followed  ever  since  its 
institution  in  the  European  quarter,  and  which  has  been  since 
copied  exactly  in  the  native  quarter.  It  has  undergone  no 
modification,  except  that  the  amount  of  oil  used  weekly  has  now 
been  reduced  considerably. 

"  The  work  in  the  European  quarter  was  begun  in  the  first 
week  in  May  1906,  and  by  the  end  of  July,  the  mosquitos  in 
this  part  of  the  town  were  sensibly  diminished.  The  summer 
was  very  hot  and  damp,  but  we  were  able  to  rest  in  the  after- 
noons without  being  bitten  by  Stegomyia.  By  the  end  of 
August  mosquitos  had  been  reduced  greatly ;  and  in  many 
parts  of  the  European  quarter  mosquito-nets  were  no  longer 
required.  But  it  was  found  that  we  were  using  an  enormous 
amount  of  oil,  nearly  3,000  gallons  of  equal  parts  crude  and 
refined  oil  per  month.  This  was  because  of  the  sewage  in  the 
cellars.  It  was  therefore  determined  to  try  to  reduce  the  amount 
of  water  in  these  cellars  permanently,  so  as  to  economise  the  oil. 
There  were  then  400  cellars  in  the  town  flooded  with  sewage, 
having  a  total  of  7,296  square  metres  water  surface. 

"  This  condition  of  insanitation  was  due  to  the  following 
peculiarity  of  the  place.  The  subsoil  water  (sea-water)  is  only 
a  metre  below  the  ground-level,  as  the  whole  spit  of  sand,  on 
which  Port  Said  is  built,  is  reclaimed  from  the  sea.  Owing  to 
the  small  area  reclaimed,  the  ground-rent  is  very  high,  and  in 
consequence  many  large  buildings,  of  often  four  and  five  and 
even  six  stories,  have  been  erected,  and  divided  into  flats  and 
suites  of  offices.  These  houses  have  been  built  with  basement 
cellars.  In  every  building  the  portion  of  the  cellars  situated 
under  the  main  entrance  hall  has  been  shut  off  by  brick  walls 
from  the  cellars  to  form  the  cesspool,  into  which  all  the  house 
drains  discharge.  These  cesspools  were  supposed  to  be  sealed 
except  for  a  ventilating  shaft,  but  were,  in  the  majority  of 
instances,  badly  built  and  leaky.  The  result  was  that  the 
sewage  was  passing  into  the  adjoining  basement  cellars  as  fast 
as  it  poured  into  the  cesspool.  Once  in  the  cellars  it  did  not 
rapidly  soak  into  the  sand  forming  their  floor,  as  at  that  level 
the  sand  was  already  saturated  with  the  subsoil  water.  So 
that  we  found  when  we  began  our  campaign,  that  in  the  400 
large  buildings  the  whole  basement  constituted  the  cesspools, 
and  in  them  mosquitos,  flies,  cockroaches,  and  other  insects 
were  breeding  in  myriads.  These  cellars  were  also  swarming 
with  rats  and  were  the  cause  of  the  perpetual  smell  of  sewage 
which  assailed  one  even  in  the  street." 

Towards  the  end  of  1906,  people  in  the  European  quarter 

2  K 


514  MOSQUITO   REDUCTION    IN   EGYPT  [Sect. 

were  beginning  to  discard  their  mosquito  curtains  and  life  was 
becoming  more  bearable,  and,  as  was  anticipated,  the  natives 
began  to  ask  why  their  quarter  was  not  treated  also.  In 
response  to  their  request,  therefore,  a  campaign  was  started 
in  the  native  quarter  in  January  1907.  A  fresh  brigade  was 
formed,  and  the  campaign  was  conducted  on  precisely  similar 
lines  to  that  in  the  European  quarter. 

The  results  at  Port  Said  have  fully  compensated  for  the  cost 
of  the  undertaking.  When  I  was  in  Port  Said  for  several 
months  in  the  spring  of  1908,  I  never  saw  a  single  mosquito — 
a  marvellous  contrast  to  my  experience  in  the  same  town  ten 
years  before.  Mosquito  curtains  are  never  used  now  by  the 
inhabitants,  and  no  precautions  whatever  are  required  to  be 
taken  against  being  bitten.^ 

The  following  table  gives  the  cost  of  the  campaign,  the 
Egyptian  Pound  being  equivalent  to  about  twenty-one  shillings. 

Year.  Amount  of  oil  used.  Total  cost. 

1906  European  quarter  only,  May 

to  December      .         ,         .     14,296  gallons.  L.E. 384768 

1907  European  and  native  quarters 

for  the  whole  year     .         .     41,120  gallons.        L.E.i,i76"275 

1908  Both    quarters.     12    months. 

Cellars  filled  up  .         .     31,670  gallons.        L.E.i,023'463 

It  will  be  noticed  that  the  amount  of  oil  used,  and  therefore  the 
cost  of  the  work,  diminishes  every  year,  and  this  should  be 
expected.  Should  the  present  cesspool  system  of  sewage  dis- 
posal ever  be  replaced  by  drainage,  the  amount  of  oil  required 
will  become  very  small,  and  the  size  of  the  gangs  could  be 
reduced,  for  there  would  be  less  work  to  be  done. 

But  the  cost  of  the  campaign  has  been  trifling  compared 
with  the  beneficial  results  to  the  community.  Everybody  has 
been  delighted  with  the  results,  fevers  have  declined,  and  the 
children  have  become  healthy.  The  streets  no  longer  smell 
as  they  did,  and  the  place  has  improved  in  every  way.     The 

^  In  1902  Sir  W.  MacGregor  and  I  were  "  devoured  alive  "  by  Stegomyia  in  Port 
Said.     During  three  visits  in  1907  and  1908  I  did  not  see  a  single  mosquito. — K.  Ross. 


53]  PORT   SAID  515 

absolute  disappearance  of  mosquitos  is  a  most  remarkable  thing, 
and  is  probably  unique  in  history ;  yet  if  the  brigades  become 
slack,  the  gnats  reappear  in  a  few  days.  The  inhabitants  now 
complain  at  once  if  mosquitos  appear,  and  their  breeding-places 
are  then  looked  for.  They  will  always  be  found  in  the  im- 
mediate neighbourhood. 

But  the  general  effect  on  the  town  is  the  most  striking 
example  of  the  efficacy  of  the  sanitary  measure.  Officials  of 
the  Government  enter  every  house  unmolested  ;  they  know  all 
that  is  going  on,  and,  in  consequence,  vice  has  been  greatly 
reduced.  Port  Said  is  no  longer  a  "sink  of  iniquity."  The 
streets  are  safe ;  there  is  less  prostitution  there  than  in  any 
town  in  Egypt ;  gambling  dens  have  disappeared  ;  all  is  known 
in  spite  of  the  Capitulations.  If  a  cesspool  bursts  or  over- 
flows, the  landlord  has  to  remedy  the  defect,  or  he  has  to 
stand  the  abuse  of  his  tenants  owing  to  the  return  of  the 
mosquitos.  Moreover,  he  is  promptly  sued  by  the  Government. 
The  consuls  themselves,  far  from  obstructing,  now  assist  the 
authorities  in  every  way. 

It  is  right  to  mention  that  the  Suez  Canal  Company,  through 
its  President,  Prince  d'Arenberg,  have  placed  a  large  sum  of 
money  for  the  maintenance  of  this  campaign  at  the  disposal  of 
the  Egyptian  Government. 

This  campaign  at  Port  Said  is  perhaps  the  most  successful 
which  has  ever  been  started,  and  any  one  who  is  able  to  com- 
pare Port  Said  in  the  old  days  with  the  present  state  of  affairs 
will,  I  am  sure,  eulogise  the  work  which  has  been  done.  A 
great  deal  remains  to  be  done,  however ;  but  the  mosquito 
campaign  has  paved  the  way  for  it,  and  has  shown  that  with  a 
little  perseverance  sanitary  reform  in  Egypt  is  not  nearly  so 
difficult  as  is  usually  made  out. 

There  can  be  no  question  that  drainage  is  the  next  thing 
required  at  Port  Said.  The  present  cesspool  system  is  quite 
inadequate,  and  it  should  be  replaced  by  proper  sewerage  as 
quickly  as  possible.     A  scheme  has  been  drawn  up  and  passed. 


5i6  MOSQUITO    REDUCTION    IN    EGYPT  [Sect. 

1  believe ;  and  I  have  heard  that  the  Suez  Canal  Company  have 
offered  to  advance  the  necessary  funds  for  it.  It  is  difficult  to 
appreciate,  therefore,  why  it  has  not  been  undertaken.  The 
Egyptian  Government  itself  appears  to  be  doing  very  little 
for  Port  Said,  but  the  least  it  might  do  is  to  accept  the  Canal 
Company's  offer  and  drain  the  town.  At  present  negotiations 
are  on  foot  between  the  Government  and  the  Company  regard- 
ing the  latter's  concession,  and  I  suppose  that  the  health  of 
Port  Said  has  suffered  for  this  delay.  The  drainage  will  be 
expensive,  for  it  will  have  to  be  done  on  the  artificial  pumping 
system,  there  being  no  *'  fall "  at  Port  Said.  Still,  drainage 
there  is  almost  more  necessary  than  at  Cairo.  If  the  place 
were  properly  drained,  the  expenses  attached  to  the  mosquito 
campaign  would  be  reduced  almost  to  a  negligible  quantity. 

Cairo. — Cairo  is  a  very  much  larger  city  than  Port  Said.  It 
contains  an  estimated  population  of  more  than  half  a  million, 
the  European  element  being  smaller  than  that  of  either  Port 
Said  or  Alexandria.  The  town  is  situated  on  the  east  bank 
of  the  Nile,  at  the  apex  of  the  delta  of  the  river.  Facing 
Cairo,  on  the  other  side  of  the  river,  there  is  the  town  of  Ghizeh, 
and  between  the  two,  on  an  island,  there  is  the  residential 
suburb  of  Ghezireh.  Cairo  proper  can  almost  be  divided  into 
two  portions — the  native  to  the  east  and  the  European  to  the 
west — by  the  old  canal,  now  filled  in  to  form  a  tramway, 
called  the  Khalig.  Suburbs  extend  to  the  north  and  south, 
but  the  city  itself  is  compact,  and,  for  its  population,  does  not 
cover  a  very  great  area.  Owing  to  the  fact  that  the  Govern- 
ment owns  most  of  the  surrounding  land  and  will  not  part 
with  it  cheaply,  the  price  of  land  is  exorbitant,  and  in  conse- 
quence there  is  great  overcrowding,  with  the  erection  of  high 
buildings  containing  residential  flats  (in  this  city,  with  its 
almost  tropical  climate). 

Cairo  is  infested  with  mosquitos.  To  destroy  them  through- 
out the  city  would  be  a  stupendous,  but  not  impossible,  task, 
and  it  would  involve  an  expenditure  of  about  ^20,000  annually. 


53]  CAIRO  517 

It  is  true  that  in  the  winter  months  the  gnats  are  not  so 
numerous,  but  in  the  summer  and  autumn  the  pest  is  as  bad 
as  in  many  tropical  places. 

Like  Port  Said,  Cairo  is  built  on  a  lake  of  subsoil  water. 
The  Nile  water,  of  course,  is  not  confined  between  the  banks 
of  the  river.  In  fact,  the  underground  river  is  much  larger 
than  the  Nile  itself,  and  it  flows  directly  beneath  the  city  of 
Cairo.  The  height  of  the  subsoil  water,  therefore,  varies  with 
the  height  of  the  Nile,  and  in  the  months  of  September  and 
October,  when  the  Nile  at  Cairo  is  in  flood,  it  frequently 
happens  that  the  basements  of  the  houses  are  filled  with  water. 

Every  house,  native  or  European,  has  its  cesspool,  which 
leads  directly  into  the  subsoil  water ;  and  for  centuries  past 
all  the  sewage  of  the  city  has  passed  directly  into  this  under- 
ground lake  and  has  saturated  the  soil  all  round.  The  cess- 
pools of  the  houses  built  by  Europeans  are  called  "  percolating 
pits."  They  are  commonly  built  immediately  beneath  the 
houses,  and  they  vary  in  size  according  to  the  uses  put  to 
them.  Their  bases  are  deficient  in  bricks  and  are  formed  by 
the  porous  earth  only.  Every  cesspool  dips  into  the  subsoil 
water,  and  bricks  are  removed  from  the  walls  in  places  to 
facilitate  the  percolation  of  the  sewage  into  the  surrounding 
earth.  It  can  veritably  be  said  that  the  land  on  which 
Cairo  is  built  is  sodden  with  sewage.  Nearly  all  the  pits  are 
ventilated  by  short  intake  and  long  uptake  shafts  carried  up 
to  the  roofs  of  the  houses,  and  it  is  by  means  of  these  pipes 
that  mosquitos  gain  access  to  the  cesspools.  A  few  of  the 
more  modern  houses  are  fitted  with  "fosses  morass,"  which 
are,  in  reality,  modified  liquefying  tanks.  Some  of  them  are 
made  on  a  fairly  satisfactory  basis,  but  usually  they  are  pre- 
tences, and  are  nothing  more  than  rather  elaborate  percolating 
pits. 

The  native  cesspool  is,  if  possible,  more  insanitary.  It 
consists  of  a  long  trough  dug  in  the  earth  under  the  house. 
Stone  flags  form  its  roof,  and  one  of  these  flags,  having  a  hole 


5i8  MOSQUITO   REDUCTION    IN    EGYPT  [Sect. 

in  it,  is  used  as  the  closet.  No  water  flushing  arrangement 
is  employed,  and  fluid  soon  soaks  into  the  earth.  For  this 
reason  mosquitos  do  not  breed  so  readily  in  the  native  as  in 
the  European  cesspools,  and  consequently  they  are  not  so 
numerous  in  the  native  as  in  the  European  quarter  of  the  city. 

Both  classes  of  cesspool  have  to  be  pumped  out  from  time 
to  time,  and  conservancy  carts  form  an  important,  if  not  an 
ornamental,  portion  of  the  Cairo  traffic.  The  pumping  out 
process  is  an  expensive  item  for  the  landlord,  and  is  a  lucrative 
business  conducted,  not  by  the  Government,  but  by  private 
enterprise.  On  the  plea  of  expense  landlords  frequently 
neglect  to  cause  the  cesspools  to  be  emptied  until  the  last 
moment.  At  present  there  are  no  drains.  For  the  last  three 
years  the  Government  has  made  a  special  drainage  department 
for  the  construction  of  sewerage.  I  have  heard  that  the  plans 
of  the  scheme  have  already  been  passed.  In  the  meantime, 
when  the  soil  is  turned  up  in  any  part  of  the  town  for  the 
purpose  of  making  the  foundations  of  new  buildings,  the  stench 
is  usually  indescribable,  for  the  subsoil  water  is  soon  reached, 
and  that  water  is  practically  sewage.  Moreover,  these  excava- 
tions form  fruitful  breeding-places  for  mosquitos. 

The  water-supply  of  Cairo  is  derived  from  shallow  wells 
placed  below  the  town,  a  source  which  has  given  rise  to  con- 
siderable controversy.  In  the  native  quarters,  almost  every 
house  has  its  own  well,  which  is  bored  close  beside  the  porous 
cesspool.  The  water  in  the  well  is  that  which  has  usually 
percolated  in  from  the  neighbouring  cesspit.  The  natives 
prefer  this  or  the  Nile  water,  which,  of  course,  is  polluted,  to 
that  supplied  from  the  wells  at  Rod  el  Farag.  When  cholera 
broke  out  some  years  ago,  many  of  the  wells  were  filled  up, 
but  they  have  nearly  all  been  reopened.  In  all  the  cesspools, 
wells  and  other  collections  of  water  which  riddle  the  city, 
mosquitos,  cockroaches,  and  all  sorts  of  vermin  thrive.  The 
human  mortality  is  enormous,  especially  the  infantile  mortality. 
The  figures  supplied  by  the    Public    Health  Department   are 


53]  CAIRO  519 

unreliable  (as  I  know,  for  I  have  assisted  to  compile  some  of 
them).  The  actual  population  is  unknown,  many  deaths  are 
probably  never  reported,  and  sickness  is  not  usually  notified. 
All  deaths  are  supposed  to  be  registered,  the  diagnosis  usually 
being  made  by  a  brief  inspection  of  the  dead  body.  Doctors 
will  not  notify  disease,  because  they  say  that  it  ruins  their 
practice.  Landlords  prefer  to  knock  holes  in  the  sides  of  their 
cesspools  and  allow  the  sewage  to  flood  their  cellars  and 
basements  rather  than  go  to  the  expense  of  having  them 
pumped  out.  The  water-supply  is  not  the  best  obtainable, 
the  streets  are  not  properly  cleaned,  and  enormous  heaps  of 
dung  and  rubbish  have  been  allowed  to  accumulate  for  years 
past  on  the  outskirts  of  the  city.  Many  of  the  streets  are  not 
metalled  ;  which  perhaps  is  a  good  thing,  for  the  rough  surface 
acts  as  a  sponge  for  the  stale  urine  which  would  otherwise 
collect  in  puddles.  Dung  and  street  refuse  are  used  as  fuel 
generally  ;  and  large  collections  of  this  rubbish  are  kept  for 
this  purpose  on  the  roofs  of  the  "  Turkish  Baths."  Nearly  all 
the  dogs  have  been  destroyed  owing  to  outbreaks  of  rabies, 
and  mangy  cats  have  taken  their  place  as  natural  scavengers. 
Hordes  of  flies,  which  breed  in  the  dung  and  rubbish,  abound 
everywhere,  and  are  nearly  as  great  a  nuisance  as  the  mosquitos. 
Without  exaggeration,  Cairo  may  be  described  as  a  city  which 
is  hardly  fit  for  habitation,  and  at  present  it  must  rank  with 
Moscow,  Pekin  and  Hankow  as  being  one  of  the  most  insanitary 
spots  in  the  world.  Since  the  mosquito  campaign.  Port  Said 
is  a  health  resort  compared  with  it. 

The  common  mosquitos  found  are  Culexfatigafis,  Stegomyia 
fasdata,  and  a  species  of  Anopheline  called  Cellia  pharoensis. 
They  breed  in  the  cesspools,  wells  and  ornamental  fountains. 
The  natives  love  fountains,  and  their  houses  always  contain 
large  numbers  of  water  vessels  of  all  sorts  and  sizes. 

Fevers  are  undoubtedly  rife.  Typhoid  broke  out  in  one 
or  more  of  the  principal  hotels  each  season  when  I  was  in 
Cairo  ;    for  it   must  be  remembered  that  Cairo  is  a   favourite 


520  MOSQUITO   REDUCTION    IN   EGYPT  [Sect. 

resort  in  the  winter.  The  typhoid  is  probably  propagated  by 
the  vegetables,  which  are  usually  washed  in  old  canals,  or 
even  cesspools,  by  the  natives  when  they  bring  them  into  the 
town.  Some  years  ago  a  scheme  was  made  to  prevent  this 
washing,  which  is  done  to  make  the  vegetables  glisten  and 
look  fresh  for  the  market ;  but  the  Government  would  not 
adopt  it.  Dengue,  which  is  probably  propagated  by  Culex 
fatigans,  occurs  in  epidemic  form  every  year.  Malaria  exists 
in  Cairo,  but  it  is  only  of  the  mild  tertian  and  quartern  types. 
Following  on  some  questions  which  were  asked  in  the  House 
of  Commons  last  year,  a  controversy  arose  in  the  Press  in 
Egypt  regarding  the  incidence  of  the  disease.  One  paper 
said  that  it  did  not  exist.  But  it  does.  Only  last  summer 
an  outbreak  occurred  at  Ghezireh,  and  according  to  the 
Statistical  Report  of  the  Public  Health  Department  for  1908, 
twenty-nine  deaths  occurred  in  Cairo  alone  from  the  disease. 
The  Senior  Medical  Officer  of  the  Egyptian  Army  reported 
an  outbreak  at  Zeitoun  and  Abbassieh  (suburbs  of  Cairo)  on 
3rd  November  1907  (Letter  No.  411).  I  have  myself  seen 
cases  of  malaria,  and  have  taken  Anophelines  frequently, 
especially  at  Ghezireh.  Probably  the  incidence  of  the  disease 
is  far  greater  than  is  commonly  supposed.  Several  other 
diseases,  such  as  Simple  Continued  Fever,  are  confounded 
with  it.  Elephantiasis,  also  conveyed  by  Culicines,  is  a  common 
complaint,  and  victims  are  frequently  seen  begging  in  the 
streets. 

A  real  estimate  of  the  incidence  of  malaria  has  never  been 
made.  Last  year  a  small  spleen  census  was  taken  among 
some  children,  but  the  result  was  vitiated  by  the  discovery 
of  a  disease,  provisionally  called  "  Endemic  Cirrhosis  of  the 
Liver,"  which  occurs  among  them.  Still,  malaria  exists,  and 
other  fevers  too  ;  which  is  sufficient  ground  for  the  institution 
of  a  campaign,  apart  from  the  other  great  sanitary  benefits 
conferred  by  these  undertakings.  At  one  of  the  campaigns, 
also,  that   at   the   Police   School,  figures   have   been   obtained, 


53]  CAIRO  521 

which  I  shall  quote  later,  and  they  demonstrate  amply  the 
beneficial  results  which  would  accrue  from  general  mosquito 
reduction.  Cairo  is  visited  annually  by  thousands  of  English 
and  American  tourists,  who  live  in  palatial  hotels,  and  who 
cannot  realise  the  real  state  of  affairs.  From  a  superficial 
visit,  Cairo  is  a  most  picturesque  city ;  but  let  them  go  off 
the  beaten  tracks  into  the  depths  of  Boulac,  Saida  Zenab,  and 
Bab  el  Sharia,  districts  which  visitors  do  not  often  see,  and 
they  will  then  appreciate  the  insanitary  precipice  whose  brink 
they  visit. 

The  first  mosquito  campaign  in  Cairo  was  started  by  a 
few  English  residents  in  the  district  of  Kasr  el  Dubarra  in 
1904  or  1905.  Only  a  few  houses  were  treated  (by  the 
residents  themselves),  and  although  a  reduction  in  the  number 
of  mosquitos  resulted,  the  campaign  soon  lapsed  owing  to 
the  fact  that  many  of  the  breeding -places  were  overlooked. 
In  the  meantime.  Sir  Horace  Pinching,  K.C.M.G.,  Director- 
General  of  the  Egyptian  Public  Health  Department,  who 
was  very  pleased  with  the  work  of  my  brother,  E.  H.  Ross, 
at  Port  Said,  gave  me  an  appointment  as  probationer  in 
that  Service,  for  which  I  abandoned  the  Medical  Service  of 
the  British  Navy — in  the  hope  of  having  better  opportunities 
for  scientific  and  sanitary  work.  In  the  autumn  of  1906,  His 
Excellency  Mansfield  Pacha,  then  the  Commandant  of  the 
Cairo  City  Police,  suggested  to  me  that  an  experimental 
campaign  should  be  instituted  privately  in  the  Muski  district 
near  the  police  headquarters.  Most  of  the  necessary  funds 
were  provided  by  the  police,  and  Mansfield  Pacha  used  his 
influence  to  get  subscriptions  from  the  other  residents  whose 
property  was  to  be  treated.  The  campaign  included  the  build- 
ing of  the  Mixed  Tribunals,  the  Opera  House  and  the  Esbekieh 
Gardens.  This  campaign  is  an  interesting  one,  for  the  whole 
area  involved  was  very  small,  about  half  a  square  mile  of 
densely-populated  buildings  situated  right  in  the  heart  of  the 
city,   where   the    houses    were,   if    possible,   more    infested   by 


522  MOSQUITO   REDUCTION    IN   EGYPT  [Sect. 

mosquitos  than  elsewhere.  The  result  was  remarkable,  for 
in  three  months  the  mosquitos  had  practically  disappeared 
from  the  area  treated,  whereas  all  round  they  remained  as 
bad  as  ever.  Every  cesspool  was  oiled  once  a  week  with 
a  mixture  of  refined  and  crude  petroleum  in  equal  parts. 
All  water  vessels  were  overturned  and  dried  out.  In  the 
Opera  House  the  audience  could  watch  the  performance  in 
comfort  owing  to  the  mosquito  campaign,  whereas  if  any  one 
crossed  the  street  to  one  of  the  uncampaigned  houses,  he 
would  be  pestered  by  hundreds  of  insects.  This  campaign 
proved  the  point  that  mosquitos  will  not  migrate  far  from 
their  original  breeding  -  places.  We  received  no  opposition 
whatever  from  the  inhabitants,  in  spite  of  the  fact  that  the 
majority  of  them  were  Europeans,  and  incidentally  hasheesh 
and  gambling  dens  were  discovered  and  reported  to  the  police. 
Early  in  1907  a  new  campaign  was  started  in  Kasr  el 
Dubarra  by  myself  under  the  orders  of  Sir  H.  Pinching.  This 
district  is  bordered  by  the  Nile  and  contains  the  best  residential 
houses  in  Cairo,  including  the  British  Agency.  It  is  right  to 
mention  that  this  campaign  was  restarted  largely  at  the 
instigation  of  Lady  Cromer,  who  suggested  that  it  might  be 
instituted  on  scientific  lines  by  a  responsible  official ;  not  by 
private  enterprise,  like  the  first  attempt  in  1904.  Sir  Horace 
Pinching  ordered  the  funds  to  be  provided  after  a  rough 
estimate  of  the  cost  had  been  prepared.  The  next  step  was 
to  obtain  permission  from  the  residents  themselves  to  allow 
us  to  enter  their  houses.  It  was  considered  preferable  to 
obtain  permission  from  individuals  rather  than  from  their 
consuls,  because  at  that  time  some  of  the  consuls  in  Cairo 
were  not  on  very  friendly  terms  with  the  Government.  Letters 
printed  in  several  languages  were  sent  to  the  residents,  and 
a  large  number  were  soon  answered  giving  permission.  The 
European  residents  never  appeared  to  object  when  they 
appreciated  that  they  would  have  nothing  to  pay — a  point 
which   was   clearly    stated    in    the   printed   letters.      Curiously 


53]  KASR   EL   DUBARRA  523 

enough,  the  only  persons  who  objected  were  the  natives  who 
had  no  right  to  refuse.  We  could,  of  course,  have  entered 
the  houses  of  the  local  subjects  without  their  permission,  but 
E^ypt  is  governed  by  a  diplomatic  administration  rather 
than  by  a  scientific  one,  and  it  seemed  more  diplomatic  to 
treat  both  native  and  European  alike.  The  objectors  were 
called  upon  and  the  campaign  explained  to  them.  Lady 
Cromer  came  to  the  rescue,  and  was  indefatigable  in  calling 
and  seeing  personally  many  of  those  who  refused  to  allow  us 
to  enter  their  houses,  and  allaying  their  suspicions.  By  the 
end  of  January  the  campaign  was  in  full  swing,  the  brigade 
consisting  of  a  European  foreman  and  two  native  labourers. 

In  about  three  months,  when  the  mosquitos  ought  to  have 
been  reappearing  owing  to  the  return  of  the  hot  weather,  the 
residents  noticed  that  their  houses  remained  practically  free, 
in  spite  of  the  fact  that  the  pest  was  assuming  its  usual  pro- 
portions in  the  other  uncampaigned  parts  of  the  city.  One 
by  one  the  objectors  asked  that  the  campaign  might  be 
instituted  in  their  houses,  for  they  began  to  realise  the  benefit 
of  it.  For  instance,  one  of  the  gentlemen  who  objected  to 
the  campaign  at  the  outset  was  a  native  prince.  His  palace, 
therefore,  was  not  entered.  After  a  few  months  his  neighbours 
began  to  complain  that  the  mosquitos  from  his  house  annoyed 
them  ;  and  he,  on  entering  their  houses,  remarked  on  the 
reduction  of  the  number  of  gnats.  Suddenly  a  polite  letter 
was  received  asking  for  a  visit  from  the  brigade,  and  the 
letter  was  followed  by  a  visit  from  the  objector  himself,  who 
implored  us  to  destroy  his  mosquitos.  From  instances  such 
as  this  we  learnt  that  it  is  better  to  ignore  objections  to  the 
visits  of  a  brigade  rather  than  to  endeavour  to  persuade  people. 
Let  the  campaign  be  continued  in  the  houses  of  others  ;  after 
a  short  time  I  think  that  it  will  be  found  that  all  objections 
will  disappear. 

The  following  October,  when  the  mosquitos  ought  to  have 
been    at    their   worst,    Kasr   el    Dubarra   enjoyed    comparative 


524  MOSQUITO    REDUCTION    IN    EGYPT  [Sect. 

immunity  from  them,  and  at  the  Semiramis  Hotel,  which  is 
in  the  district,  visitors  and  tourists  could  sleep  without  mosquito 
curtains,  the  only  place  of  this  nature  in  Cairo  where  this  has 
ever  been  done. 

At  the  beginning  of  1907,  on  the  initiative  of  Sir  H. 
Pinching  and  Major  Elgood,  a  small  campaign  was  also  started 
by  me  in  the  Police  School  at  Cairo.  This  school  contained 
about  five  hundred  students,  recruits  for  the  Police  Force  in 
Egypt,  and  it  was  established  in  an  old  palace  in  the  Abdin 
quarter  of  the  city.  The  palace  is  a  very  large  building  sur- 
rounded by  a  garden.  It  is  built  on  the  native  plan  in  the 
shape  of  a  quadrangle  with  a  large  courtyard  in  the  centre. 
It  was  infested  with  mosquitos,  from  which  the  students  suffered 
greatly.  The  ceiling  of  the  school  hospital,  which  formed 
part  of  the  building,  used  to  be  black  with  the  gnats,  a  sight 
I  have  never  seen  before.  Like  many  of  these  native  palaces, 
there  were  more  than  seventy  latrines,  all  of  the  native  pattern, 
which  communicated  with  large  cesspools  under  the  building. 
These  cesspools  were  not  ventilated,  and  the  only  access  to 
them  was  through  the  closets  themselves  which  led  directly 
into  them.  In  the  garden  there  were  the  inevitable  fountains, 
and  a  sort  of  pond  which  was  used  for  irrigation  purposes. 
Oil  used  to  be  poured  down  most  of  the  latrines  ;  others  were 
sealed  up.  The  pond  and  fountains  were  emptied.  The 
number  of  mosquitos  was  greatly  reduced  in  a  very  short 
time,  and  before  I  left  Cairo  a  year  later,  they  had  practically 
disappeared.  Major  Elgood,  the  Commandant  of  the  school, 
then  kindly  undertook  to  supervise  this  campaign,  and  when, 
at  a  later  date,  the  school  was  moved  to  new  buildings  at 
Abbassieh,  a  fresh  campaign  has  been  started  there  by  him 
with  most  successful  results.  The  year  before  this  campaign 
was  started,  26  to  27^  of  ^he.  personnel  were  admitted  to  hospital 
suffering  from  various  forms  of  fever,  including  dengue  and 
simple  continued  fever  (probably  some  were  cases  of  malaria). 
After  the  campaign  had  been  in  progress  for  some  time,  the 


53]  HELUAN  525 

fever  showed  a  decline,  thus — June  1908  to  June  1909,  the 
incidence  of  fever  fell  to  7"2%.  The  average  number  of  the 
personnel  is  about  five  hundred.  In  a  paper  describing  this 
campaign/  Major  Elgood  gives  the  following  figures : — Year 
1907-1908,  eighty-eight  cases  of  dengue  occurred.  During  the 
year  1908- 1909,  when  the  campaign  was  in  progress,  the  number 
of  cases  fell  to  six. 

In  March  1907  a  campaign  was  started  at  Heluan  by  myself 
under  the  orders  of  Sir  H.  Pinching.  The  initial  procedure 
was  similar  to  that  adopted  at  Kasr  el  Dubarra.  Heluan  is 
a  town  built  in  the  desert  about  15  miles  to  the  south  of 
Cairo.  It  is  famed  as  a  health  resort  owing  to  its  hot  sulphur 
springs  and  dry,  invigorating  climate.  There  are  many  hotels 
and  sanatoria,  and  the  town  itself  is  a  growing  one  considerably 
larger  than  Ismailia.  The  reason  why  Sir  H.  Pinching  ordered 
the  campaign  to  be  started  at  Heluan  was  because  malaria 
existed  there.  Anophelines  had  been  taken,  and  examination 
of  blood-films  taken  at  random  from  native  children  demon- 
strated benign  parasites ;  an  examination  which  had  been 
made  sometime  previously  by  Dr  Dreyer  of  the  Public  Health 
Department. 

A  new  brigade  was  formed,  and  all  the  water  collections 
and  cesspools  were  treated  with  petroleum.  Mosquitos  were 
found  to  be  breeding  in  some  pools  of  sulphur  water,  which 
had  collected  in  some  places  owing  to  overflow  from  the  sulphur 
wells.  It  seems  that  after  this  water  has  been  allowed  to  stand 
for  some  time,  the  sulphur  precipitates,  and  the  larvae  of 
mosquitos  (including  these  of  Cellia  pJiaroensis)  will  then  thrive 
in  it.  An  attempt  was  made  to  drain  this  surplus  water,  which 
will  be  an  expensive  undertaking.  In  the  meantime,  as  much 
of  it  as  possible  was  oiled. 

Heluan  was  famed  almost  as  much  for  its  mosquitos  as  it 

^  "Some  Account  of  the  Preventive  Measures  taken  "against  Mosquitos  at  the 
Police  School,  Cairo,"  by  Major  1*.  G.  Elgood.  Cairo  Scientific  Journal^  No.  34, 
vol.  iii.,  and  Brit.  Med.  Journ.,   i6th  Oct.   1909. 


526  MOSQUITO    REDUCTION    IN    EGYPT  [Sect. 

was  for  its  sulphur  baths  ;  even  in  the  winter  months  one  was 
being  bitten  night  and  day.  Nearly  all  the  gardens  have 
fountains,  but  unlike  the  houses  in  Cairo,  the  cesspools  are 
usually  to  be  found  in  the  garden  or  courtyard.  Stegomyia 
breed  freely  in  the  fountains,  which  were  therefore  stocked  with 
fish.  Some  householders  objected  to  oil  being  poured  into  the 
fountains  because  it  is  unsightly,  and  it  was  found  that  a 
common  variety  of  Nile  fish  ( Tilapia  nilotica)  is  very  hardy  and 
will  keep  small  collections  of  water  free  from  larvae.  The 
cesspools  are  constructed  very  deeply  in  Heluan,  as  the  subsoil 
water,  especially  in  the  east  and  north  of  the  town,  can  only  be 
found  at  a  considerable  depth.  There  are  not  many  water- 
closets,  and  the  result  is  that  some  of  the  cesspools  are  dry 
except  in  "  pockets  "  which  have  formed  in  the  earth.  To  reach 
these  "  pockets  "  with  oil,  it  was  frequently  necessary  to  send  a 
man  down  into  the  cesspool  itself.  In  this  case  a  rule  was 
made  that  a  lighted  candle  was  previously  lowered  to  test  for 
the  presence  of  poisonous  gases  —  an  important  precaution 
against  accident. 

The  results  of  the  campaigns  in  Cairo  and  Heluan  may  be 
summed  up  together,  for  in  every  case  it  was  practically  the 
same.  The  number  of  mosquitos  began  to  diminish  perceptibly 
in  about  three  months ;  and  in  Heluan,  in  six  months,  people 
were  sleeping  without  mosquito  curtains.  Even  those  people 
who  were  inclined  to  doubt  the  possibility  of  ridding  districts 
of  Cairo  of  mosquitos,  had  to  admit  that  the  destruction  of  the 
pest  is  not  only  a  possible,  but  really  an  easy  problem. 

In  September  1907  Dr  Dreyer  again  examined  blood-films 
from  some  children  in  Heluan,  and  found  that  very  few  parasites 
could  now  be  demonstrated.  No  cases  of  dengue  occurred  there 
during  the  autumn  of  the  same  year,  although  an  epidemic  of 
the  disease  was  in  progress  in  other  parts  of  Egypt, 

Apart  from  the  prevention  of  disease,  however,  mosquito 
campaigns  are  valuable  measures  to  be  adopted  in  a  country 
like  Egypt,  for  they  bring  the  officials  who  organise  them  more 


53]  RESULT  527 

in  touch  with  the  inhabitants,  who,  consisting  largely  of  natives, 
are  inclined  to  mistrust  those  set  above  them.  Mosquito  brigades 
are  constantly  visiting  the  houses,  and  when  the  inhabitants 
appreciate  that  something  is  really  being  done  for  them,  they 
take  an  interest  in  the  work,  and  ultimately  further  this  and 
other  sanitary  reforms.  When  I  left  Egypt  in  January  1908 
there  was  no  one  who  objected  to  the  visits  of  the  mosquito 
brigades,  nor  were  there  any  complaints  that  any  member  of 
them  had  abused  the  privileges  conferred  on  European  subjects 
by  the  Capitulations.  In  fact,  the  Capitulations  put  little  real 
difficulty  in  the  way  of  sanitary  reform.  Europeans  and  their 
consuls  are  fully  alive  to  the  possibilities  of  scientific  measures 
properly  carried  out ;  and  if  Europeans  and  even  natives  are 
assured  that  efforts  to  improve  sanitation  are  made  con- 
scientiously, I  believe  that  they  will  forego,  as  has  been  proved 
by  the  mosquito  campaigns,  the  one  privilege  which  they 
prize,  namely,  an  immunity  against  interference  by  Government 
officials.  The  difficulty  caused  by  the  domicile  clause  of  the 
Capitulations,  which  is  used  as  a  cloak  for  nearly  all  adminis- 
trative sins,  vanishes  in  the  face  of  a  mosquito  campaign.  The 
experience  gained  in  Cairo  and  Heluan  proves  conclusively  that 
mosquito  destruction  is  a  desirable  measure  to  be  adopted  in 
Egypt,  and  it  is  remarkable  that  this  fact  was  not  appreciated 
before. 

Unfortunately,  Sir  Horace  Pinching,  who  had  been  so 
sympathetic  towards  this  work,  retired  in  the  autumn  of  1907 
from  his  post  of  Director-General  of  the  Department.  His 
successor  immediately  told  me  that  he  did  not  consider  it 
necessary  for  me  to  continue  the  work,  and  he  treated  me  in 
such  a  manner  that  I  was  obliged  to  resign  my  appointment  in 
the  Department.  At  the  same  time  my  brother,  E,  H.  Ross, 
was  also  threatened  in  my  presence  with  dismissal.  It  will 
therefore  be  understood  that  since  these  events  the  Government 
has  become  lethargic  about  anti-mosquito  measures.  1  have 
heard  that  mosquitos  have    returned  in  the  parts  campaigned 


528  MOSQUITO   REDUCTION   IN   EGYPT  [Sect. 

in  Cairo ;  and  at  Heluan,  and  even  Port  Said,  the  pest  is 
reappearing.  I  have  seen  frequent  complaints  in  the  Egyptain 
newspapers  that  the  campaigns  have  been  allowed  to  fail,  and 
I  fear  that  for  the  time  being  mosquito  destruction  has  fallen 
into  disrepute  in  Egypt. 

From  my  experience  of  the  Public  Health  Department, 
I  think  that  the  Government  does  not  appear  to  appreciate 
its  responsibility  regarding  sanitary  administration.  A  visit 
to  Cairo  will  show  that  nearly  all  improvements  are  made 
by  private  enterprise.  When  a  new  town  is  started,  such  as 
Heliopolis  Oasis,  it  is  started  by  a  company.  The  most  modern 
buildings  in  the  city  itself,  erected  for  the  public,  have  been 
built  by  His  Highness,  the  Khedive,  on  his  own  private  property. 
Yet  the  Government  owns  nearly  all  the  vacant  land  round  the 
city,  and  it  refuses  to  part  with  it.  The  result  is  that  the 
city  is  becoming  overcrowded,  with  an  enormous  death-rate. 
Calculated  on  the  1907  census,  the  death-rate  of  Cairo  was, 
for  1908,  39"23  per  1,000,  and  for  1909,  44*9  per  1,000.  In  an 
article  published  in  the  British  Medical  Journal  on  loth  April 
1 910,  which  describes  the  state  of  the  sanitation  of  Cairo,  it  is 
stated  that  28*2%  of  the  infants  born  in  Cairo  die  during  the 
first  year  of  life  ;  and  48'5%,  or  nearly  half,  of  the  children  born 
will,  if  the  present  death-rate  continues,  die  before  they  reach  the 
age  of  sixteen  years.  When  I  was  in  Cairo,  in  certain  districts 
in  the  Saida  Zenab  quarter,  known  as  El  Mardi  and  El  Sakkia, 
Government  properties,  the  death-rate  reached  20^,  and  yet  the 
Government  will  not  allow  the  city  to  expand,  and  appears  to 
await  a  rise  in  the  value  of  the  property  before  it  will  part  with 
it.  My  personal  opinion  is  that  the  fault  is  due  to  the  fact  that 
the  country  is  governed  almost  by  amateurs.  The  sanitary 
officers  are  not  bound  to  obtain  Public  Health  Diplomas,  and 
it  seems  to  me  that  many  of  the  higher  Government  offices  are 
placed  in  the  hands  of  friends  and  relatives  of  existing  officials, 
apparently  without  regard  as  to  qualification.  I  have  shown 
that  the  laws  are  difficult   to  enforce.     There  is  no  building 


53]  REMARKS  529 

law  whatever ;  anybody  can  build  any  hovel  he  pleases.  Few 
reports  are  published  from  the  Public  Health  Department,  and 
officials  under  the  present  regime  are  not  permitted  to  print  the 
results  of  their  work  for  the  benefit  of  their  successors. 

Mosquito  extermination,  however,  is  bound  to  be  undertaken 
seriously  in  Egypt  under  more  competent  management.  For 
the  time  being,  perhaps,  it  will  remain  in  abeyance,  but  it  is  a 
measure  which  is  so  certain  in  its  results  and  so  far-reaching  in 
the  good  which  it  does,  that  before  long,  I  think,  it  will  be 
generally  demanded  by  the  public.  It  is  nauseating  to  live  in 
Cairo  in  the  summer  and  to  be  bitten  persistently  by  insects 
which  breed  in  excrement.  Mosquito  destruction  is  an  un- 
pleasant though  a  simple  problem.  It  must  be  continued 
unremittingly,  or  the  gnats  will  return ;  but  the  cost  of  the 
campaign  will  fall  to  a  certain  extent  after  the  initial  destruction 
of  the  pest.  I  hope  that  the  work  will  be  started  throughout 
Cairo,  for  I  know  that  the  results  will  be  greater  than  were  ever 
anticipated. 


By  ANDREW  BALFOUR,  M.D,  B.Sc,  F.R.C.P.  Edin., 
D.P.H.  Camb. 

Director,  Wellcome  Research  Laboratories,  Gordon  College,  and 
Medical  Officer  of  Health,  Khartoum 

54.  The  Campaign  at  Khartoum.  —  In  the  pre  -  Dervish 
days  Khartoum  must  have  been  a  hot-bed  of  mosquito  Hfe. 
This  is  apparent  from  the  evidence  of  Sir  Rudolph  Baron  von 
Slatin,  who  states  that  mosquitos  were  very  prevalent  during 
this  period,  and  from  that  of  Father  Ohrwalder  of  the  Austrian 
Mission,  who  asserts  that  he  was  sometimes  driven  to  go  and 
stand  up  to  his  neck  in  the  Nile  in  order  to  avoid  the  attentions 
of  the  winged  hordes.  That  malaria  was  also  present  cannot 
be  doubted.  Schweinfurth  speaks  of  the  unhealthiness  of  the 
place  in  a  manner  which  leaves  little  doubt  but  that  one  of 
the  chief  causes  of  the  high  mortality  which  obtained  at  certain 
periods  was  malarial  fever.  It  is  believed  that  its  evil  reputa- 
tion was  one  of  the  reasons  which  induced  the  Mahdi  to 
abandon  its  site  altogether,  and,  with  that  empirical  wisdom 
which  often  characterises  the  native,  to  found  Omdurman  on 
a  spot  where  the  river  banks  are  not  bold  and  terraced  but 
shelving,  and  consequently  free  from  pools  at  low  Nile.  Some 
four  years  after  the  new  city  had  come  into  being,  a  survey  of 
the  conditions  as  regards  mosquito  prevalence  was  made.  This 
disclosed  the  fact  that  three  genera,  represented  by  three  species, 
were  constantly  present,  namely,  in  order  of  frequency,  Culex 
fatigans,  Stegoniyia  calopus  and  Pyretophorus  costalis.  Malaria 
was  found  to  exist,  and  it  was  shown  that  infection  could  be 
acquired  locally,  while  numerous  cases  were  always  being 
brought  into  the  town  by  steamers  coming  from  the  highly 
malarious   regions  to  the  south.     It  was  towards  the  close  of 

530 


Sfxt.  54]  BREEDING-PLACES  531 

1903  that  anti-mosquito  measures  were  instituted  and  a  small 
mosquito  brigade  established.  These  measures  have  continued 
in  force  ever  since,  and  the  brigade  has  been  constantly 
employed ;  for  one  of  the  chief  points  elucidated  by  the  work 
is  the  absolute  necessity  for  its  continuity.  In  a  place  like 
Khartoum  it  is  essential  to  carry  out  preventive  measures 
year  in  and  year  out,  and  two  mottoes  most  suitable  for  those 
in  charge  might  well  be  "  Weary  not  in  well-doing,"  and  "  Do 
not  put  overmuch  trust  in  the  native  inspector." 

In  this  brief  note  we  are  only  concerned  with  the  single 
species  of  Anopheline  which  constitutes  itself  a  danger  to  the 
town,  and  may  omit  any  detailed  account  of  the  work  in 
connection  with  the  two  other  species  of  Culicid  mentioned  ; 
but  it  is  well  to  point  out  that  in  practice  these  latter  cannot 
be  neglected.  Mosquito  prevention  measures  must  be  general, 
and  it  is  very  often  the  operations  against  Culex  or  Stegomyia 
which  lead  to  the  discovery  of  invasion  or  threatened  invasion 
by  Pyretophorus. 

P.  costalis,  then,  is  the  malaria  carrier  of  the  Northern 
Sudan,  and  so  far  as  Khartoum  is  concerned  its  breeding-places 
were  found  to  consist  of: — 

(i)  Pools  left  by  the  falling  Blue  Nile.  These  are  found 
for  the  most  part  in  the  sand-banks  which  appear  in 
the  river's  bed,  but  may  also  occur  in  the  sloping 
and  terraced  banks  as  the  river  falls. 

(2)  Garden  tanks. 

(3)  Bath-waste  pits. 

(4)  Permanent  garden  pools, 

(5)  Sakia  pits,  as  used  in  irrigation  work. 

(6)  Irrigation  channels  and  pools  formed  by  leaking 
"  gudwals,"  as  the  large  and  small  canals  are  termed. 
The  only  large  area  of  irrigated  land  is  at  Khartoum 
North. 

(7)  Wells. 

(8)  Rain-water  collections. 


532  THE   CAMPAIGN   AT   KHARTOUM  [Sect. 

(9)  Household  water  collections,  such  as  water  stored  in 
barrels.     These  are  not  at  all  common. 

(10)  Water   collections    on    steamers,   provided   these  be 

exposed  to  the  light,  i.e.,  in  boiler  trays,  cisterns,  etc. 

(11)  Chance  water  collections,  as  in  old  barges  and  leaky 
boats  where  speedy  water  evaporation  is  prevented. 

One  or  two  of  these  breeding-places  merit  a  few  words  of 
explanation.  The  soil  in  some  parts  is  what  is  termed  "weep- 
ing." It  contains  a  large  quantity  of  salt.  Hence  if  gudwals 
are  constructed  of  this  soil  the  water  dissolves  out  the  salts, 
and  leakages  soon  result,  pools  form,  and,  despite  the  fact 
that  the  water  is  brackish,  P.  costalis  readily  lays  her  eggs  in 
such  collections.  This  mosquito  is  very  rarely  found  in  wells, 
but  its  larvae  have  once  been  encountered  in  a  well  70  feet 
in  depth.  This  is  so  peculiar  that  one  wonders  if  they  had 
not  been  accidentally  introduced.  Rain-water  collections  are 
rare  in  Khartoum,  but  occasionally  the  summer  is  compara- 
tively wet,  and  then  pools  and  puddles  may  persist  for  some 
time.  They  are  not  commonly  utilised  as  breeding  -  places 
by  P.  costalis.  This  Anopheline  is  not  often  found  breeding 
out  on  the  river  steamers,  but  has  been  known  to  do  so,  and 
may  be  introduced  into  Khartoum  as  imagines  both  by  steamers 
and  by  native  boats.  Recently  a  species  of  Nyssorhynchus 
has  been  apparently  introduced  in  this  manner.  It  is  worth 
noting  that  since  operations  were  started  cases  of  malaria 
locally  acquired  in  Khartoum  have  never  once  occurred  with- 
out the  presence  of  Anophelines  in  or  near  the  town  being 
demonstrated. 

The   chief    methods   of    prevention    and    reduction    put   in 
force  may  be  tabulated  as  follows  : — 
(i)  Systematic  inspection. 

(2)  Notification  of  cases  of  malaria. 

(3)  The    issue    of    warning    notices    and    distribution    of 

information. 

(4)  Petrolage. 


54]  DETAILS    OF    MOSQUITO   REDUCTION  533 

(5)  Filling  in  of  pools  and  abolition  of  water  collections 

such  as   garden   tanks,  bath-waste  pits,  etc.     Also 
the  screening  of  cisterns. 

(6)  The  introduction  of  fish  into  water  channels. 

(7)  The  piping  and  covering  of  raised  water  channels  to 

prevent  leakage  through  their  banks. 

(8)  The  imposition  of  fines. 

(9)  General  legislation   as   regards   borrow  pits,  irrigation, 

engineering  work,  and  the  provision  and  maintenance 

of  dry  zones. 
All  three  forms  of  malaria  used  to  occur  in  Khartoum. 
Benign  tertian  was  the  most  common,  malignant  next,  while 
quartan  was  rather  infrequently  encountered,  though  it  has 
been  found  to  be  much  commoner  than  was  at  first  supposed. 
Quite  a  large  number  of  cases  harbouring  crescents  annually 
come  into  the  town  from  the  Upper  Nile  and  the  Bahr-el- 
Ghazal  Province. 

Some  of  these  measures  call  for  a  little  further  notice.  The 
inspection  must  be  thorough  and  the  native  inspector  must 
be  controlled  by  trained  and  reliable  British  sanitary  inspectors. 
The  town  is  divided  into  sections,  each  of  which  is  in  charge 
of  a  native  who  has  no  sooner  completed  his  round  than  he 
begins  again.  In  this  way,  if  he  does  his  work  properly  the 
inspector  should  visit  every  house  and  every  water  collection 
in  his  district  at  least  once  a  week.  The  British  inspectors 
are  responsible  for  the  whole  town,  and  often  combine  mosquito 
work  with  house-to-house  inspection.  Areas  bordering  on  the 
river,  the  point  of  danger,  are  in  charge  of  the  most  experi- 
enced men,  and  a  special  native  inspector  is  detailed  for 
steamer  and  boat  work.  Khartoum  has  a  population  of  some 
16,000;  Khartoum  North,  of  about  25,000;  and  there  are  in 
all  at  the  present  time  three  British  sanitary  inspectors^  and 
seven  native  inspectors.  Of  these  one  British  and  two  native 
inspectors   are   responsible   for    Khartoum    North,  where   with 

^  Mosquito  prevention  is,  of  course,  only  a  part,  though  an  important  one,  of  the 
work  of  these  inspectors. 


534 


THE   CAMPAIGN   AT    KHARTOUM 


[Sect. 


the  exception  of  some  pools  on  a  sandy  island  there  are  no 
river  pools,  the  banks  being  high  and  steep,  and,  where  there 
are  scarcely  any  gardens,  the  only  dangerous  area,  so  far  as 
P.  costalis  is  concerned,  being  a  large  stretch  of  irrigated  land 
and  certain  small  irrigation  channels  which  are  apt  to  leak 
and  form  pools.  The  dockyard  is  situated  at  Khartoum  North, 
and  the  steamers  require  constant  attention,  but  more  for  Culex 
and  Stegomyia  than  for  Pyretophorus.  When  necessary,  extra 
men  are  employed  filling  in  river  pools  ;  and  if  these  happen, 
as  at  present,  to  exist  in  sand-banks  opposite  the  so-called 
British  Barracks,  the  services  of  the  British  troops  tenanting 
these  latter  are  at  once  solicited,  and  never  in  vain. 

Notification  has  proved  of  great  value.  It  stimulates 
enquiry  and  has  often  led  to  the  discovery  of  breeding-places 
when  such  would  otherwise  have  been  missed. 

Here  are  types  of  the  warning  notices  inserted  at  intervals 
in  the  local  press,  especially  during  the  winter  when  the  Nile 
is  falling,  and  again  during  the  brief  rainy  season  in  August 
and  September. 


SANITARY   NOTICES 


"The  attention  of  householders 
and  others  is  again  called  to  the 
necessity  of  properly  emptying  and 
drying  out  zeers  and  other  vessels 
holding  water  at  least  once  a  week, 
in  order  to  prevent  mosquitos  find- 
ing breeding-places.  Persons  pro- 
ceeding on  leave  are  especially 
requested  to  see  that  this  is  done 
before  premises  are  left  vacant. 
Any  one  found  harbouring  mosquito 
larvae  or  pupae  on  his  premises  is 
liable  to  be  punished  in  accordance 
with  Town  Regulations  ;  and  in 
future  stringent  action  will  be  taken 
to  put  an  end  to  this  nuisance 
and  danger  to  health.  It  is  not 
enough  to  instruct  servants  to  carry 
out  these  measures.  There  must 
be  personal  supervision.  Five 
minutes  per  week  is  no  great  tax 
on  the  time  of  any  one." 


"  Householders  are  urgently  re- 
quested to  give  immediate  notice 
to  the  Sanitary  Inspector  at  the 
Mudiria  if  they  find  themselves 
troubled  by  mosquitos  or  note  their 
presence.  Any  one  found  harbour- 
ing larvae  or  pupae  on  his  premises 
is  liable  to  be  fined  ;  and  stringent 
action  will  be  taken,  as  malaria- 
carrying  species  are  at  present 
endeavouring  to  obtain  a  footing 
in  the  town." 


54]  ANTI-LARVAL   MEASURES   ON   STEAMERS  535 

The  regulations  as  regards  steamers  are  of  practical  interest 
and  are  also  given  below.  When  carefully  followed  the  results 
have  been  excellent. 

"  I.  Before  leaving  Khartoum  the  bilge  water  in  the  various 
sections  should  be  oiled  by  pouring  petroleum  on  the  surface 
of  the  water  and  stirring  well  with  a  stick.  A  film  will  then 
form  on  the  surface,  which  prevents  access  of  air  to  the  mosquito 
larvae  and  pupae,  and  so  kills  them.  Eggs  deposited  by  mosquitos 
on  this  oil  film  will  not  develop,  and  many  of  the  females 
themselves  will  be  killed.  Roughly,  about  one  half-pint  of 
oil  should  be  devoted  to  each  section.  A  little  experience 
soon  shows  how  much  or  how  little  oil  is  needed  to  form  a 
proper  film.  In  addition,  the  water  in  the  trays  under  the 
boilers  should  be  examined,  and,  if  necessary,  oiled. 

"  A  cup  or  wide-mouthed  bottle  can  be  used  for  collecting 
water  for  examination.  The  vessel  should  be  quickly  but 
gently  dipped  under  the  surface  and  lifted  out  without  spilling 
any  of  the  contents.  For  somewhat  inaccessible  places  a  tin 
with  its  bottom  replaced  by  wire-gauze  mesh  and  attached  to 
a  stick  is  useful.  The  larvae  are  then  found  wriggling  on 
the  gauze.  Such  a  collecting  dish  is  easily  made  and  answers 
well.  It  should  be  examined  in  a  good  light.  It  is  to  be 
remembered  that  any  standing  water  collections  will  harbour 
mosquito  larvae,  and  attention  should  therefore  be  paid  to 
the  water-closet  cisterns,  zeers  and  tanks. 

"  2.  During  the  voyage,  opportunity  should  be  taken  to  re- 
oil  the  bilges  wherever  possible.  This  should  especially  be 
the  case  before  starting  on  the  return  journey.  Wood  holds 
are  usually  at  fault.  The  difficulty  can  be  got  over  by  empty- 
ing these  in  rotation,  so  that  the  water  in  the  hold  can  be 
got  at  and  oiled  once  in  every  fortnight.  Special  attention 
should  be  directed  to  zeers  when  these  are  used  for  storing 
bottles  of  drink.  All  zeers  should  be  emptied  out  at  least 
once  a  week  during  the  voyage. 

"  3.  The  thing  to  be  avoided  is  returning  to  Khartoum  with 
mosquitos  on  board.  If  this  is  done,  wells  and  water  collections 
in  the  town  which  have  been  cleared  at  trouble  and  expense 
are  liable  to  become  reinfected.  This  has  happened  repeatedly, 
so  that  it  is  very  important  that  steamers  should  arrive  clean 
and  free.  It  is  well  to  have  all  bilge  water  emptied  on  arrival, 
and  all  steamers  lying  up  should  be  inspected  and  treated 
in  the  manner  described.  Similar  precautions  are  required 
as  regards  barges,  sandals,  launches  and  any  vessel  on  which 
there  is  stagnant  water. 


536  THE   CAMPAIGN    AT   KHARTOUM  [Sect. 

"Note. — It  has  been  proved  that  mosquitos,  as  a  rule,  will 
not  stay  for  any  length  of  time  on  a  steamer  if  they  are 
prevented  from  breeding  out  on  board.  Consequently,  such 
preventive  methods  are  effective,  as  has  been  demonstrated 
on  several  occasions  ;  and  there  is  no  excuse,  in  most  instances, 
for  steamers  reaching  Khartoum  with  their  bilge  water,  etc., 
full  of  larvae  and  pupae,  and  their  cabins  full  of  adult  mosquitos. 

"  Sometimes  it  has  been  found  advisable  to  employ  sulphur 
squibs  when  there  were  many  adult  insects  in  the  holds." 

A  little  space  may  be  devoted  to  the  introduction  of  fish 
which  has  been  successfully  employed  in  the  irrigation  channels 
at  Khartoum  North  and,  as  will  be  seen,  elsewhere  in  the 
Sudan. 

A  zealous  and  interested  official  some  time  ago  suggested 
the  introduction  of  the  small  "  millions '"  fish  {Girardinus  poecil- 
loides)  from  Barbados  to  cope  with  larvae  in  swamps,  irrigation 
channels,  large  pools  and  like  collections  of  water.  The  question 
was  referred  to  me,  and  I  found  myself  opposed  to  the  idea, 
partly  because  I  know  the  difficulty  of  transporting  these  fish, 
and  the  possibility  that  they  might  not  take  kindly  to  new 
surroundings,  and  partly  because,  like  the  proud  Syrian  of 
old,  I  was  tempted  to  reply :  "  Are  not  Abana  and  Pharpar, 
rivers  of  Damascus,  better  than  all  the  waters  of  Israel  ? "  In 
other  words,  one  was  of  opinion  that  there  was  no  use  going 
outside  for  what  might  very  well  be  obtained  at  home.  I  knew 
that  Captain  Flower,  Director  of  the  Zoological  Gardens  at 
Ghizeh,  employed  young  "  Bulti  "  {Tilapia  niloticd)  in  the  tanks 
of  the  aquarium  at  Ghezireh,  and  found  them  most  efficient  in 
keeping  the  water  free  from  mosquito  larvae,  and  it  was  reason- 
able to  suppose  that  many  Nile  fish  were  effective,  especially  as 
it  is  found  that  when  fish  are  present  in  any  pool  left  by  the 
falling  river,  mosquitos  do  not  breed  out  therein. 

There  were  two  points,  however,  requiring  attention.  If  any 
water  collection  is  stocked  with  fish,  these  latter  are  apt  to  be 
speedily  cleared  out  by  natives  or  birds,  such  as  king-fishers, 
which  are  very  plentiful.     Moreover,  as  is  explained  later,  fish 


54]  LARVIVOROUS    FISH  537 

which  attain  any  size  are  not  suitable  for  use  on  irrigated  land. 
Hence,  it  was  desirable  to  find  a  small  and  greedy  fish  which 
would  offer  no  temptation  to  the  native,  which  could  be  used 
in  irrigation  channels,  and  which,  though  not  immune  from 
the  depredations  of  fish-loving  birds,  yet  was  so  prolific,  or 
could  be  used  in  such  numbers,  as  to  make  these  ravages  of 
little  account.  The  type  of  fish  desired  was  that  known  in 
India  as  the  Chilwa  {Chula  argentea),  which  is  said  to  be  more 
efficient  than  "  millions,"  as  not  only  does  it  devour  the  larvae 
but,  being  a  surface-feeder  and  an  eager  fly-taker,  it  is  deadly 
to  the  adult  mosquito,  especially  to  the  female  intent  on  egg- 
laying. 

As  Mr  Harold  King,  our  entomologist,  was  going  up  the 
White  Nile  in  the  Floating  Laboratory  on  a  voyage  of  discovery, 
I  asked  him  to  take  every  opportunity  of  studying  the  question. 
Mr  King  is  an  excellent  field-naturalist,  and  admirably  fitted 
to  carry  out  such  an  investigation.  His  report,  which  I  append, 
will  be  found  of  interest  and  value,  and  it  would  appear  that 
in  Cyprinodon  dispar  we  have  obtained  the  fish  we  require. 
This,  as  Mr  King  remarks,  remains  to  be  proved,  but  the 
following  letter,  kindly  sent  me  by  the  Acting  Manager,  Sudan 
Plantations  Syndicate,  in  whose  irrigation  channels  the  fish 
are  being  tested,  is  at  least  promising : — 

"Dear  Sir, — In  reply  to  your  favour  of  the  19th  inst. 
I  have  examined  the  small  canal  into  which  the  fish  have  been 
introduced. 

"  The  canal  is  about  thirty  metres  long  and  about  half  a  metre 
deep,  and  the  opening  to  the  larger  canal  is  closed  with  gauze- 
wire  netting  to  keep  other  fish  out.  Although  the  still  water 
is  now  lying  twenty-five  days  there  are  no  signs  of  mosquito 
larvae. 

"  The  fish  are  alive  and  seem  to  feed  on  flies  on  the  surface 
of  the  water,  and  are  most  active  in  the  early  morning. — Yours 
faithfully,  Alex.   MacIntyre." 

Like  Mr  King,  I  ha\'e  fed  Ophiocephalus  obscurus  {vide  infra) 
on   the  larvae   of  Pyretophorus   costalis,    and    noted    how    the 


538  THE   CAMPAIGN   AT   KHARTOUM  [SecT. 

latter  were  devoured  before  ever  they  reached  the  bottom  of 
the  jar. 

The  following  is  Mr  King's  report : — 

"While  on  the  White  Nile,  between  the  dates  of  17th  April 
and  19th  July,  I  carried  out  some  investigations  with  Nile  fish 
with  a  view  to  ascertaining  what  species,  if  any,  were  likely 
to  be  of  value  in  controlling  mosquitos  by  feeding  on  their 
larvae.  In  most  of  the  swamps,  where  mosquito  larvae 
abounded,  shoals  of  small  fish  of  various  species  also  occurred, 
but  from  the  fact  that  the  two  throve  together  it  was  evident 
that  the  fish  were  not  likely  to  be  of  very  much  use.  Numbers 
of  these  fish  were  captured,  placed  in  jars  and  offered  mosquito 
larvae,  but  with  one  exception  they  refused  them  until  they 
had  passed  one  or  more  days  without  food.  The  exception 
was  a  fish  found  in  a  khor  between  Gebel  Ahmed  Aga  and 
the  river.  In  this  khor  very  few  mosquito  larvae  could  be 
found — a  search  of  nearly  two  hours  resulted  in  less  than  a 
dozen  specimens  being  taken — but  there  were  present  numbers 
of  the  young  fry  which  has  been  identified  by  Mr  G.  Boulenger 
of  the  British  Museum  as  Ophiocephalus  obsairus. 

"  This  fish  feeds  greedily  on  mosquito  larvae,  thrives  well  in 
captivity  and  in  stagnant  water,  and  appears  to  be  an  ideal 
fish  for  the  purpose  for  which  it  is  wanted,  except  in  one 
respect,  viz.,  size.  When  full  grown  it  attains  a  length  of 
35  centimetres.  As  fry,  inhabiting  shallow  waters  such  as  are 
found  in  swamps  and  river-spills,  this  fish  would  no  doubt  prove 
of  value,  for  it  is  in  just  such  places  that  mosquitos  breed.  On 
the  other  hand,  though  the  fish  would  flourish  in  large  irriga- 
tion canals,  and  the  fry  could  reach  the  smaller  gudwals  on 
irrigated  land,  the  latter  are  frequently  so  constructed  that  the 
young  fish  on  increasing  in  size  could  not  regain  the  parent 
canals  and  would  perish.  Hence  this  species  of  fish  is  not 
likely  to  be  an  economical  means  of  dealing  with  mosquito 
larvae  in  such  situations. 

"  Some  thirty  specimens  of  0.  obscurus  are  still  living  in  a  jar 
in  the  Laboratories. 

"  During  May,  I  met  Mr  Butler,  superintendent  of  game 
preservation,  who  told  me  of  a  small  fish — Cyprinodon  dispar — 
which  lives  in  Khor  Arbat,  about  twenty-two  miles  from  Port 
Sudan.  He  very  kindly  furnished  me  with  some  notes  on  its 
habits,  and  recommended  that  it  should  be  given  a  trial  as  it 
appeared  to  him  to  be  likely  to  give  good  results.  He  further 
said  that,  while  no  mosquitos  are  noticeable  in  the  vicinity  of 


54]  LARVIVOROUS    FISH  539 

that  khor,  they  are  plentiful  near  other  similar  khors  where 
C.  dispar  does  not  exist. 

"  Accordingly,  on  6th  September,  I  left  for  Khor  Arbat  and, 
having  spent  three  days  there,  returned  to  Khartoum  on  12th 
September.  There  were  myriads  of  the  fish  in  the  khor,  but 
at  first  I  had  considerable  difficulty  in  persuading  them  to  live 
in  captivity.  Eventually,  I  found  that  while,  if  placed  in  jars 
nearly  full  of  water,  most  of  them  died  within  twelve  hours, 
yet  if  given  only  about  two  inches  of  water  over  a  layer  of  sand 
they  could  be  transported  fairly  easily.  One  hundred  and  one 
living  specimens  reached  Khartoum,  and  were  there  offered 
mosquito  larvae,  which  they  took  readily.  This,  however,  is 
not  conclusive  proof  that  C.  dispar  feeds  on  mosquito  larvae  in 
its  wild  state,  as  the  specimens  had  been  unfed  for  two  days 
when  the  larvae  were  given  them,  none  being  obtainable  at 
Khor  Arbat. 

"  As  these  fish  did  not  thrive  in  jars  I  wrote  to  Mr  Maclntyre, 
Acting  Manager  of  the  estate  at  Zeidab,  belonging  to  the 
Sudan  Plantations  Syndicate  Ltd.,  asking  him  if  he  would 
allow  them  to  be  placed  in  a  gudwal  on  the  Company's  estate 
for  purposes  of  experiment.  This  he  readily  agreed  to  ;  so  that 
on  19th  September  I  took  those  that  were  still  alive — about 
seventy  in  number  —  to  Zeidab,  and  the  following  morning 
liberated  them  in  a  short  length  of  gudwal  which  Mr  Maclntyre 
very  kindly  had  filled  with  water.  This  gudwal  is  not  used,  at 
present,  for  agricultural  purposes,  and  the  pipe  connecting  it 
with  the  canal  has  been  netted  to  prevent  other  fish  gaining 
access.  This  was  done  in  order  that  the  C.  dispar  might  be 
given  every  chance  of  establishing  themselves  before  being 
subjected  to  the  possible  ravages  of  other  and  larger  fish. 

"  The  specimens  liberated  at  Zeidab  were  all  immature,  as  it 
was  found  that  partially-grown  fish  withstood  captivity  better 
than  did  adults. 

"  When  full  grown,  C.  dispar  attains  a  length  of  8  centimetres, 
and  in  all  stages  appears  to  prefer  shallow  water. 

"  Should  the  gudwal  in  which  these  fish  were  liberated  remain 
free  from  mosquito  larvae  during  the  coming  year,  while  similar 
gudwals  in  the  immediate  vicinity  serve  as  breeding-places  for 
these  pests,  I  think  sufficient  proof  of  their  value  will  have  been 
obtained  to  justify  an  effort  being  made  on  a  larger  scale  to 
establish  C.  dispar  throughout  all  the  gudwals  on  the  Sudan 
Plantations  Syndicate  Ltd.'s  estate,  and  on  other  similar  farms 
where  great  difficulty  is  experienced  in  controlling  mosquitos." 

As  regards  legislation  the  following  irrigation  rules,  imposed 


540  THE   CAMPAIGN   AT   KHARTOUM  [Sect. 

on  all  who  take  up  land  with  a  view  to  cultivation  on  a  large 
scale,  may  be  quoted  with  advantage.  They  are  of  very  great 
importance  both  from  the  sanitar}'  and  the  economic  standpoint. 

"  I.  Irrigation  channels  should  be  constructed  on  a  higher 
level  than  the  surrounding  land,  so  that  when  the  flow  of  water 
in  them  ceases  they  may  drain  dry. 

"2.  They  should  be  constructed  of  such  material  and  in  such 
a  manner  as  to  prevent  leakage. 

"  3.  Their  banks  and  beds  should  be  kept  in  good  repair,  and 
the  beds  even,  to  prevent  the  formation  of  pools. 

"4.  'Dead  ends'  of  irrigation  channels  should  be  reduced  to 
the  smallest  size  compatible  with  efficiency,  so  that  water  will 
not  stagnate  in  them. 

"  5.  Vegetation  should  be  periodically  cleared  out  of  the 
channels. 

"  6.  Sluices  should  be  constructed  so  that  there  is  no  leakage 
to  form  stagnant  puddles. 

"  7.  Where  possible,  fish  should  be  introduced,  and  kept  in 
the  main  channels  to  destroy  the  larvae. 

"  8.  Lands  where  water  is  apt  to  stand  should  have  proper 
surface  drainage. 

"  9.  Crops,  such  as  sugar-cane,  rice  and  others  which  require 
to  stand  in  water,  should  not  be  grown  within  half  a  mile  of  any 
town  or  village. 

"  10.  If  an  engine  or  pump  should  happen  to  break  down, 
particular  care  should  be  taken  to  deal  with  stagnant  pools,  and 
petroleum  should  be  used  when  necessary. 

"II.  Cases  of  malarial  fever,  and  any  prevalence  of  mosquitos, 
should  be  notified  to  the  governor  of  the  provinces  by  the 
manager  of  the  concession." 

The  above  is  a  brief  outline  of  the  measures  adopted  and 
the  work  accomplished.  What  has  been  the  result?  It  is 
difficult  to  give  comparative  statistics,  as  we  do  not  know 
how  much  malaria  used  to  be  locally  acquired  in  Khartoum  ; 
but  we  do  know  that  P.  costalis  used  to  be  fairly  common, 
especially  at  certain  times  of  the  year ;  while  now  it  is  wholly 
absent  during  many  months,  and  if  it  does  invade  the  town 
its  breeding  operations  are  usually  quickly  checked,  it  does 
not  multiply,  and  soon  disappears.  As  a  direct  consequence 
locally   acquired    malaria   has   become   very  rare.     One   cannot 


54]  RESULTS  541 

wholly  trust  the  notifications,  but  they  afford  considerable 
indication  of  how  matters  stand,  and,  so  far  as  Egyptian  and 
British  troops  are  concerned,  are  trustworthy.  Here,  then, 
are  the  locally  acquired  cases  for  the  past  few  years. 

Year  Civil  Egyptian  British 

population,  military  troops 

Oct.  to  Sept.  About  3,000  men  (One  battalion) 

inclusive.  most     of     them  about  600  men 

very  susceptible  changed  annually, 
to  infection. 

1904-05  Seven  cases  in  all.     Not  stated  according  to  population 

attacked.     Unsatisfactory  notification. 

1905-06  2(?)                              ?                                8 

1906-07  441 

1907-08  210 

1908-09  142 

1909-10  2                               ...                               4 

(to  date) 

(i6th  January  1910) 

It  is  very  rare  for  a  British  official  or  European  resident 
to  acquire  malaria  in  Khartoum  itself,  while  I  should  say  that 
owing  to  increased  trade  and  communication  more  cases  are 
now  imported  than  was  previously  the  case.  There  can  be 
no  doubt  that  if  operations  were  suspended  Khartoum  would 
speedily  regain,  if  not  its  old  evil  notoriety,  at  least  a  certain 
measure  of  the  same.  At  the  time  of  writing  there  is  a  good 
deal  of  malaria  in  the  neighbourhood  of  the  town,  i.e.,  in  villages 
a  couple  of  miles  to  the  north,  in  one  part  of  Omdurman, 
and  at  various  places  along  the  White  Nile.  Anophelines 
now,  as  previously,  are  endeavouring  to  obtain  a  footing  in 
the  town,  and  have  been  blown  into  it  by  the  wind  or  brought 
into  it  by  boats.  As  a  result,  we  have  had  a  few  cases,  mostly 
in  British  soldiers  who  were  wont  to  wander  out  to  the  east 
of  their  quarters  towards  a  part  of  the  river  where  there  are 
extensive  sand-banks  and  many  pools,  some  2\  miles  from 
the  centre  of  the  city.  Had  operations  not  been  in  force  I  am 
very  certain  that  this  year  would  have  witnessed  an  epidemic ; 
for  conditions  seem  specially  favourable  to  the  propagation 
of  P.  costalis  at  present,  and,  as  stated,  there  is  much  malaria 


542  THE   CAMPAIGN   AT   KHARTOUM  [Sect.  54 

in  the  neighbourhood.  A  measure  which  has  had  good  effects 
is  to  put  any  dangerous  area  out  of  bounds  for  British  troops. 
One  may  conclude  by  stating  that  Khartoum  is  a  favour- 
able place  for  carrying  Professor  Ross's  methods  into  effect ; 
and  that  they  have  met  with  marked  success,  and  doubtless 
will  continue  to  do  so,  provided  the  work  is  carried  out  con- 
tinually, thoroughly,  consistently  and  with  intelligence,  that 
the  influence  of  immigration  is  borne  in  mind,  and  that  legisla- 
tion provides  for  the  control  of  irrigation  and  the  regulation 
of  irrigated  areas. 


By  Dr  L.  BOSTOCK 

District  Surgeon,  Komatipoort,  Transvaal 

55.  Malaria  in  South  Africa. — British  South  Africa  as  a 
whole  does  not  suffer  much  from  malaria.  Along  the  east 
coast,  in  Portuguese  East  Africa,  Swaziland  and  Zululand,  the 
disease  is  common  enough,  and  occasional  outbreaks  occur  in 
a  few  parts  of  the  Cape  Colony  and  Natal.  A  recent  outbreak 
in  Durban  assumed  serious  proportions. 

In  the  Transvaal  the  disease  is  endemic  in  the  Low  Veldt,  in 
the  east  and  north  of  the  country  ;  and  the  type  is  severe,  bilious, 
remittent  and  haemoglobinuric  forms  being  common.  Owing 
to  paucity  of  population  in  these  districts  the  disease  attracted 
little  attention  until  the  building  of  the  Pretoria-Delagoa  Bay 
railway  line,  when  the  heavy  death-rate  forced  the  disease  upon 
the  public  notice.  No  effort  was,  however,  made  to  combat  the 
disease  until  I  was  appointed  District  Surgeon  here,  and  com- 
menced to  make  representations  to  Government  on  the  sub- 
ject in  1903.  The  work  was  started  in  1904,  and  immediately 
its  results  were  obvious  in  a  greatly  reduced  sick-rate.  The 
Railways  thereupon  instructed  me  to  make  a  fever  survey  of 
the  main  line  and  the  Barberton  branch,  and  to  make  recom- 
mendations for  each  station.  I  obtained  the  assistance  of  the 
Government  Entomologist,  the  late  Mr  C.  B.  Simpson,  for  this 
survey,  and  our  recommendations,  being  promptly  carried  out, 
resulted  in  a   considerable   reduction   of  fever  along  the  line. 

543 


544  MALARIA   IN   SOUTH   AFRICA  [Sect. 

Every  station  and  ganger's  cottage  from  Komatipoort  to 
Waterval  Onder  was  dealt  with,  local  measures  for  mosquito 
reduction  carried  out,  and  all  railway  quarters  in  the  Low  Veldt 
made  mosquito-proof  We  were  compelled  to  rely  chiefly  on 
the  latter  method  of  fever  prevention,  owing  to  the  small 
number  of  persons  concerned,  and  the  great  amount  of  work 
necessary  to  deal  with  the  breeding-places  along  the  Crocodile 
River,  which  runs  parallel  to  the  line.  All  small  breeding- 
places  in  the  immediate  neighbourhood  of  the  stations  were 
dealt  with. 

To  the  Central  South  African  Railway  belongs  the  credit  of 
first  efforts  to  combat  malaria  in  the  Transvaal,  and  since  1905 
the  apathy  of  the  public  and  the  authorities  has  been  gradually 
overcome.  The  results  obtained  by  the  Central  South  African 
Railway  proved  a  powerful  argument,  and  now  the  value  of 
anti-malarial  measures  is  fully  recognised  by  private  residents 
and  the  different  Government  departments  who  have  officials 
in  this  part  of  the  Transvaal.  Practically  every  private  resident 
in  this  town  has  now  a  mosquito-proof  bedroom  ;  and  in  the 
country  many  farmers  have  also  adopted  this  precaution. 
Mosquito-proof  quarters  are  being  provided  for  all  police  posts 
in  the  Low  Veldt,  and  also  for  the  officials  of  the  Government 
Game  Reserve,  which  lies  north  of  the  Crocodile  River.  The 
Colonial  Secretary's  Department  have  now  arranged  to  issue 
free  quinine  in  all  fever  districts  in  the  Transvaal  to  all  indigent 
whites  and  all  natives ;  the  Barberton  municipality  have  lately 
taken  up  the  subject ;  and  a  League  has  been  founded  for  the 
purpose  of  carrying  on  the  anti-malarial  campaign  throughout 
the  district. 

Anti- malaria  methods  employed  at  Komatipoort.  —  Anti- 
malarial work  was  commenced  at  Komatipoort  in  1904,  the 
cost  being  borne  by  the  Central  South  African  Railways.  The 
town  is  rather  unfortunately  situated,  in  the  angle  between  the 
Crocodile   and    the    Komati    Rivers.      Along   both   rivers   are 


fe-,>  -^ 


I.    AN    EXCELLENT    TVl'E    OF   MOSQUITO-I'KOOK    HOL'SE    AS    lUILT    HY    THE 
TRANSVAAL  GOVERNMENT. 

The  residence  of  Major  Hamilton,  Warden  of  the  Sabi  Government  Game  Reserve. 
\'ie\vs  of  front  and  iiack  of  house. 


A  SHOOTING  CAMP  ON  THE  LOW"  VELDT. 

Portable  folding  mosquito-proof  beds. 


2.    AN   EXAMPLE   OF    ROUGH    BUT    EFITCIENT  MOSQUITO   PKOOFLNG    IN    THE    VELDT. 

A  hut  at  Sabi  Bridge,  Game  Reserve.  Transvaal,  fornierl}-  occupied  by  the  Warden, 

Major  Hamilton. 


AN    AFRICAN    "  RONDHAVliL,"    AS    MOSQUITO-PKOOF   SLKEPING-QUAKTF.RS. 


3.    AN    l.\(.l-.MiH  .1    lUKA. 

A  military  block  house,  Ijought  as  it  stood  after  the  war,  converted  by  addition 
of  door  and  \vindo.\s  into  a  very  comfortable  niosiiuito-proof  bedroom. 


TWO-ROn.\rF.I1   WOOD   AXn   iron-   house   with   MOSQUITO-I'ROOF   vf.raxda. 

As  built  by  the  C.S.A.R.  for  temporary  quarters  at  the  Sabi  Uridj^e,  Selali  Railway. 

Cost  about  ;/,i8o. 


4.    A   GOOD    EXAMl'l.E   UF    .MoSQUFro-l'Kool     HuL'SF. 

The  Customs  quarters,  Komatipoort. 


^fb^'"^ 


5.    JOINT   OFFICKS    OF    THE    WlTWATEKSKANl)    XATIVK   LAIiOUK    ASSOCIATION,    AND   THE 
PORTUGUESE    DEPARTMENT    OF    EMIGRATION    AT    RESSAXE    GARCIA,    PORTUGUESE 
EAST   AFRICA. 
Natives  receiving  their  passes  tiirough  tlie  sliding  window  in  the  netting.     (The  tear 
is  in  the  photo  film,  not  in  the  netting.) 


55]  KOMATIPOORT  545 

backwaters,  pools  and  inlets,  with  dense  vegetation  in  parts, 
and  below  the  junction  lie  some  acres  of  broken,  rocky  ground 
holding  innumerable  small  pools.  The  worst  breeding-place 
of  Anophelines,  however,  was  a  swamp  running  parallel  to  the 
railway  and  opposite  the  station.  The  swamp  was  fed  by  a 
small  spring  and  surface  drainage,  and  by  the  waste  water  from 
the  pump  and  engine  sheds.  It  consisted  of  about  two  acres 
of  ground  only,  but  the  whole  of  it  was  a  network  of  small 
pools  amongst  thick  reeds  and  rank  vegetation.  Anopheline 
mosquitos  were  breeding  here  in  great  abundance,  and  it  was 
decided  to  obliterate  this  swamp  entirely.  A  brick  and  cement 
drain  was  cut  through  the  centre  to  carry  off  the  water  supply 
which  maintained  it.  The  ground  was  cleared,  all  pools  filled 
in,  and  the  surface  evenly  graded  from  each  side  down  to  the 
drain  to  carry  off  the  rainfall.  The  reclaimed  ground  was 
planted  with  banana  trees  and  eucalyptus,  and  absorption  of 
water  by  these  has  sufficed  to  keep  the  area  perfectly  dry, 
and  the  former  swamp  is  now,  on  a  small  scale,  a  town 
plantation.  Efficient  treatment  of  the  main  rivers  was  im- 
possible on  the  score  of  expense ;  but  the  portions  of  them 
within  half  a  mile  of  the  town  were  dealt  with  by  filling 
in  some  pools  by  rubble  and  cement,  and,  a  mosquito 
gang  having  been  organised,  larger  pools  were  treated  with 
paraffin. 

These  methods  proved  in  practice  to  be  most  satisfactory. 
Only  partial  reduction  of  mosquitos  had  been  attempted,  but 
it  was  subsequently  found  most  difficult  to  discover  any 
specimens  of  Anophelines  within  the  town  area. 

At  the  same  time  all  railway  servants'  quarters  were  made 
mosquito-proof,  and  the  reduction  of  fever  cases  was  marked 
and  immediate. 

The  following  table  is  taken  from  a  report  on  the  subject 
made  to  the  General  Manager  of  the  Central  South  African 
Railway  in  December  1905. 

2  M 


546 


MALARIA   IN    SOUTH   AFRICA 


[Sect. 


1903 

1904 

1905 

212 

396 

55 

230 

341 

42 

277 

405 

43 

281 

320 

33 

207 

192 
60 

40 
20 

175 

61 

10 

209 
80 

63 
3S 

4 
18 

191 

41 

28 

217 

20 

25 

9 

8  (to  7th  Dec.) 

Cases    of    malarial    fever    among    Central    South    African 
Railway  employees — Komatipoort — Kaapmuiden  section  : — 


January  . 

February 

March 

April 

May 

June 

July 

August 

September 

October  . 

November 

December 


The  above  figures  are  gross  details,  and  represent  each  case 
counted  for  every  day  of  illness,  that  is,  they  are  "  days  lost "  by 
the  whole  of  the  railway  staff.  The  actual  daily  average  of  the 
number  of  sick  during  March  1905  is  i"38,  against  a  similar 
average  for  the  same  month  in   1904  of  i3"o6. 

The  work  of  proofing  the  quarters  was  begun  in  June  1904. 

Portuguese  East  Africa. — With  the  exception  of  the  town  and 
district  of  Lourenco  Marques  nothing  has  been  undertaken,  but 
the  Portuguese  authorities  have  taken  up  the  subject  with  great 
energy  in  the  town  of  Lourenco  Marques,  with  the  result  that 
the  town,  once  extremely  unhealthy,  is  now  comparatively  free 
of  the  disease. 

The  Municipal  Health  Officer,  Dr  Amaral  Leal,  has  con- 
trolled the  work,  while  the  Government  Entomologist,  Mr 
C.  W.  Howard,  has  carried  out  an  investigation  of  the  local 
mosquito  problem.  Their  methods  have  been  the  draining  of 
a  swamp,  which  was  the  chief  breeding-ground  ;  organisation 
of  anti  -  malarial  sanitary  measures  ;  appointment  of  special 
sanitary  inspectors,  with  power  to  inspect  all  houses  and  com- 
pounds, and  to  enforce  the  carrying  out  of  their  instructions  ; 
the  treatment  of  all  breeding  -  places  ;  and  the  netting  of 
Government  offices  and  quarters.^ 

^  In  speaking  of  anti-malarial  measures  in  Louren9o  Marques,  I  should  like  to 
put  on  record  the  great  service  rendered  on  this  subject  by  A.  W.  Bayly,  Esq. ,  the 


55]  SOUTH    AFRICAN    MOSQUITOS  547 

All  offices  and  quarters  on  the  Portuguese  railway  between 
Komatipoort  and  Lourenco  Marques  are  now  mosquito-proof. 

Mosquitos. — The  following  is  a  list  of  the  mosquitos  which 
are  prevalent  in  this  Colony.  The  larger  number  of  them  were 
collected  at  Nelspruit  in  the  season  of  1904- 1905. 


Anophelina. 

Nyssorhynchus  pretorietisis.  Pyretophorus  cincrcus. 

Myzorhynchus  mauritianus.  Do.  nianhalli. 

Do.  maculipalpis.  Do.  costalis. 


CULICINA. 

Culex  bostocki.  Culex  transvaleiisis. 

Culex  sitnpsoni.  Culex  7nmuius. 

Culex  theileri.  Culex  bifoliata. 

Culex  hirsutipalpis.  Culex  salisbrunensis. 

Culex  fatigans.  Stegomyia  fasciata. 

Culex  tigripes.  Stegomyia  simpsoni. 

In  addition  to  these  there  are  a  dozen  other  species  of  rare 
genera,  which  as  far  as  we  know  as  yet  are  of  but  little  or 
no  economic  importance.  In  the  early  part  of  the  season  the 
commonest  Anopheles  mosquito  at  Nelspruit  is  P.  cinereus, 
and  later  in  the  season  N.  mmirilianus  and  N.  maculipalpis. 
The  former  is  much  more  abundant  than  the  latter,  especially 
in  March  and  April,  It  seems  that  the  abundance  of  these 
last  two  mosquitos  is  quite  parallel  with  the  abundance  of 
fever.  While  all  of  these  may  carry  fever,  the  two  latter  are, 
in  our  opinion,  the  most  important  agents  of  transmission. 
Stegomyia  fasciata  is  by  far  the  most  abundant  mosquito  in 
the  Low  Veldt.  It  is  followed  by  C.  simpsoni,  C.  hirsutipalpis, 
and  S.  simpsoni  in  order  of  abundance.  —  From  Bostock  and 
Simpson  [1905]. 

I  have  obtained  from  Mr  Howard,  the  Chief  of  the  Ento- 
mological Section  of  the  Agricultural  Department,  Lourenco 
Marques,  the  attached  report  on  the  Anophelines  for  the  Province 
of  Mozambique. 

proprietor  and  editor  of  the  Lourenco  Marques  Guardian.  He  was  among  the  first 
householders  in  the  town  to  make  his  house  mosquito-proof,  and  has  spared  no  trouble 
to  extend  a  knowledge  of  the  subject  by  constant  references  to  it  in  his  paper. 


548 


MALARIA   IN   SOUTH    AFRICA 


[Sect.  55 


Report  by  C.  W.  HOWARD,  Esq.,  B.A.,  F.E.S. 

Chief  of  the  Entomological  Section,  Department  of  Agriculture 
for  Mozambique 

Distribution  of  Anophelines  in  Mozambique 

In  my  collections  in  Lourengo  Marques  District,  Gazaland, 
and  about  the  Zambesia,  I  have  taken  several  Anophelines. 
The  commonest  is  Pyretophorus  costalis.  It  seems  to  be 
distributed  all  along  the  coast,  and  is  without  doubt  the 
principal  carrier  of  malaria.  I  have  always  found  it  wherever 
I  found  people  suffering  from  malaria.  It  is  very  abundant 
in  the  flats  about  Lourenco  Marques,  breeding  even  in  the 
brackish  marches  along  the  shores  of  the  bay.  Careful  notes 
were  made  of  this  mosquito  last  season,  and  it  was  found 
that  its  increase  and  decrease  almost  exactly  coincided  with 
the  rise  and  fall  of  malaria  cases  in  town.  They  seem  to 
hibernate  over  the  dry  season,  in  such  places  as  grass  huts 
and  stables,  although,  if  favourable  places  exist,  they  ma}'- 
breed  throughout  the  year  in  sheltered  localities.  This,  how- 
ever, seems  to  be  the  exception.  The  same  mosquito  is  also 
very  abundant  along  the  Zambesia  and  about  Quelimane. 

Another  Anopheline  fairly  common  on  the  coast  is  Alyzor- 
hynchus  niauritianus.  I  have  taken  this  on  the  Limpopo  and 
Maputo  rivers,  but  not  about  Lourenco  Marques.  It  frequents 
houses  in  company  with  P.  costalis,  but  not  in  such  large 
numbers. 

NyssorJiynchiis  pretoriensis  also  occurs  along  the  coast.  My 
specimens  seem  to  have  been  taken  from  Lourenco  Marques 
District. 

An  apparently  new  species  of  Anopheles  also  occurs  here,  and 
is  now  being  named  by  Mr  Knab  of  Washington. 

Of  mosquitos  other  than  Anophelines  our  commonest  species 
along  the  coast  are  : — 


Stegomyia  calopus   Mey.,  our  com- 
monestmosquitonexttoCy^^//^a«J^ 
Scutomyia  sugens  Wied. 
Stegomyia  sitnpsoni  Theob. 
Culex  luteolateralis  Theob. 
Culex  univittatus  Theob. 
Grabhainia  durbanensis  Theob. 
Culex  transvaalensis  Theob. 


Taeniorhynchus  aurites  Theob. 
Matisonia  uniformis  Theob. 
Culex  theileri  Theob. 
Culex    fatigans    Wied.       Common 

everywhere. 
Culex  thalassius  Theob. 
Eretmapodites  n.  sp. 
Heptaphlebomyia  simplex  Theob. 


By  p.  MURISON,  M.D.,  B.Sc,  D.P.H. 
Medical  Officer  of  Health,  Durban 

56.  Epidemic   of  Malaria  in   Durban,    1905-1907.  —  Malaria 

broke  out  in  Durban  during  January  1905,  and  the  number 
of  cases  rapidly  increased  until  the  cooler  autumn  weather 
set  in.     The  following  table  shows  the  monthly  notifications : — 

Summer.  Autumn.  Winter. 


January.         February.  March.         April.         May.  June.         July. 

12  85  612  1,084       1,877  497  135 

Some  parts  of  Zululand  are  so  unhealthy  from  the  presence 
of  malaria  that  they  are  uninhabitable. 

In  Durban,  malaria  has  been  a  compulsorily  notifiable 
infectious  disease  since  1902,  and  as  a  result  an  average  of 
seventy  cases  were  notified  per  annum,  as  existing  in  the 
borough.  All  these  cases  were  found  on  enquiry  to  have 
contracted  the  disease  elsewhere,  and  had  come  to  Durban 
to  recuperate. 

No  definite  information,  either  from  professional  or  lay 
persons,  can  be  obtained  to  show  that  malaria  had  ever  existed 
as  a  local  infection  within  the  borough  of  Durban  previous 
to  1905.  Within  a  fortnight  of  the  1905  outbreak  every  medical 
man  in  Durban  had  recognised  many  cases. 

The  borough  of  Durban  consists  somewhat  roughly  of  a 
triangle,  one  side  being  bounded  by  the  Indian  Ocean,  another 
by  the  waters  of  Durban  Bay,  and  the  base  is  formed  by  a 
range  of  low  hills,  in  extent  about  6  miles,  which  stretches 
from   one  end  of  the  borough   to  the  other.     From   the  base 

of  these  hills  to  the  water's  edge  there  is  a  plain,  being  about 

549 


550  EPIDEMIC    OF   MALARIA   IN    DURBAN  [Sect. 

i^  miles  in  greatest  width,  and  probably  averaging  about  15 
feet  above  high-water  mark.  All  classes  of  houses  are  to  be 
found  on  this  plain. 

Chiefly  along  the  base  of  these  hills,  this  flat  area  is  at 
its  lowest  level,  and  contains  many  swampy  areas,  some  of 
quite  small  size,  others  extending  to  scores  of  acres. 

The  slope  of  the  hills  (Berea)  extend  to,  roughly,  about  a 
mile  from  the  plain  to  their  summit,  and  on  this  gradual  rising 
ground  have  been  erected  dwellings  of  all  classes. 

The  notifications  received  during  the  first  few  months 
distinctly  localised  malaria  into  many  areas,  and  these  were 
found  to  be  always  in  close  proximity  to  swampy  or  water- 
logged lands. 

When  malaria  broke  out,  I  decided  to  rigidly  follow  the 
teachings  of  Professor  Ronald  Ross,  and  this  has  been  adhered 
to  throughout. 

It  was  recognised  from  the  beginning  that  in  order  to  cope 
with  the  disease  both  temporary  and  permanent  measures  were 
necessary. 

The  permanent  improvements  were  to  consist  of  such  work 
as  (i)  The  drainage  of  surface  and  water-logged  and  swampy 
areas.  The  cutting  of  new  watercourses  and  the  extension 
of  old  ones.  (2)  The  filling  in  of  swampy  areas,  pools,  etc., 
and  the  levelling  and  grading  of  land  to  enable  stormwater 
to  flow  towards  some  drain  or  watercourse.  Such  measures 
naturally  removed  for  all  time  the  pools  and  swamps  necessary 
for  the  larvae  stage  of  mosquito  development.  Since  1905 
the  borough  has  expended  on  this  class  of  work  approximately 
^80,000. 

The  temporary  measures  consisted  of  the  formation  of  a 
mosquito  brigade,  whose  work  was  to  consist  of  dealing 
immediately  with  all  pools  or  areas  of  swampy  lands  which 
were  the  habitat  of  mosquito  larvae  by  means  of  larvicides 
such  as  paraffin  and  disinfectants. 

We  discovered  that  the  crudest  and  cheapest  disinfectants 


56]  MEASURES   ADOPTED  551 

were  the  best  for  larvae  destruction,  and  we  used  disinfectants 
where  pools  were  shallow,  or  where  reeds  existed  in  considerable 
numbers.  We  found  it  not  only  cheaper  but  more  efficient 
to  use  disinfectant  under  such  circumstances.  One  part  of 
disinfectant  to  five  thousand  parts  of  estimated  water  in  the 
pool  was  found  to  be  effectual.  Paraffin  was  used  where  pools 
were  deep,  and  where  an  unbroken  film  could  be  formed. 

Many  substances  were  tried  as  larvicides,  and  some 
mechanical  ingenuity  was  shown  by  those  in  charge  of  the 
work  in  endeavouring  to  improve  the  process  of  application 
of  the  larvicides. 

As  permanent  improvements  are  carried  out,  the  area  of 
temporary  measures  was  naturally  reduced,  and  it  may  be 
stated  that  the  only  part  of  the  borough  of  Durban  requiring 
any  temporary  measures  now  is  practically  confined  to  that 
part  known  as  the  Eastern  Vlei. 

It  was  also  recognised  that  the  education  of  the  inhabitants 
of  the  borough  regarding  the  natural  history  of  malaria  was 
a  necessary  auxiliary  aid  in  the  work  of  prevention.  We 
believed  that  a  much  more  whole  -  hearted  assistance  would 
be  more  readily  obtained  if  some  facts  regarding  the  disease 
were  freely  spread  about  so  that  the  rationale  of  the  work 
and  the  orders  required  to  be  carried  out  by  householders 
were  more  clearly  understood  and  appreciated.  Hand  -  bills 
dealing  with  malaria  prevention  were  left  at  all  houses  in  which 
cases  of  malaria  had  been  notified  to  exist,  and  in  some  areas 
these  hand-bills  were  left  at  every  house.  Lectures  and  magic 
lantern  demonstrations  were  given  by  me  to  societies,  institu- 
tions, schools,  etc. ;  and  I  feel  sure  these  lectures  and  demonstra- 
tions were  a  potent  agent  for  good  in  our  campaign. 

The  mosquito  brigade  consisted  of  two  Europeans  and  about 
fifty  Indians.  Every  swampy  part  where  larvae  could  breed 
out  being  treated  every  ten  days  or  thereby,  so  as  to  render 
their  development  impossible. 

Present  position. — In   1907   the  number  of  freshly  -  infected 


552  EPIDEMIC   OF   MALARIA   IN    DURBAN  [Sect. 

cases  were  very  few  in  number.  From  a  circular  issued  to 
all  the  medical  practitioners  of  Durban  (for  we  had  stopped 
compulsory  notification  of  the  disease  owing  to  the  excessive 
cost  in  1906),  the  total  number  of  cases  would  probably  be 
less  than  a  hundred.  At  the  same  time,  immediately  outside 
the  borough,  every  household,  European  and  coloured,  was 
down  with  the  disease,  and  the  deaths  amongst  Indians  in 
particular  were  enormous.  This,  in  my  opinion,  was  a  brilliant 
object  lesson  as  to  the  efficiency  of  the  preventive  measures 
employed  within  the  borough.  Durban  can  be  invaded  from 
the  neighbouring  country  from  both  ends,  the  swampy  lands 
here  being  continuous.  On  the  reverse  slope  from  Durban 
of  the  Berea  hills  the  descent  to  the  Umgeni  Valley  is  fairly 
steep.  This  valley  was  saturated  with  malaria  in  1907,  but 
no  invasion  of  the  borough  took  place  from  this  direction. 
The  hill  (500  feet)  seems  to  act  as  an  effectual  barrier.  At 
each  end  of  the  ridge,  however,  where  invasion  did  occur,  an 
area  or  zone  was  formed,  in  which  permanent  and  temporary 
measures  were  carried  out  as  efficiently  and  quickly  as  possible. 
Fresh  cases  which  occurred  in  the  borough  in  that  year  were 
almost  wholly  confined  to  these  areas.  Government  recog- 
nised the  necessity  for  dealing  with  the  excessive  sickness  and 
mortality  in  the  area  lying  in  contiguity  to  our  borough,  and 
started  an  anti-malarial  movement  towards  the  end  of  the 
season,  but  too  late  to  be  of  any  practical  benefit  for  that  year. 
In  Durban  during  1908  permanent  improvements  were  still 
carried  out  and  temporary  measures  maintained.  No  cases 
occurred  within  the  borough.  Outside  the  borough,  where 
the  disease  had  been  rampant  the  previous  year,  and  where 
no  preventive  measures  of  any  kind  were  being  taken,  no 
fresh  cases  of  malaria  occurred.  The  disease  seemed  to  have 
suddenly  left  Durban  County. 

The  measures  which  have  been  carried  out  in  Durban  in 
order  to  exterminate  malaria  have  added  very  much  to  the 
comfort  of  life,  as  well  as  to  the  salubrity  of  the  town.     Water 


56]  RESULTS  553 

tanks  and  cisterns  which  were  an  adjunct  of  every  house, 
although  rendered  quite  unnecessary  owing  to  the  bountiful 
supply  of  water  introduced  into  Durban,  were  still  retained  in 
position  full  of  water,  probably  more  through  apathy  than 
anything  else.  These  were  all  ordered  to  be  removed  by  the 
Sanitary  Department.  These  tanks  did  not  form  breeding- 
places  for  Anopheles^  but  Culex  developed  in  them  in  great 
numbers.  With  the  vigilance  which  is  still  being  maintained, 
Durban  may  be  said  to  be  at  present  practically  free  from 
mosquitos  of  any  kind.  In  fact,  the  presence  of  a  few  mosquitos 
in  a  house  is  at  once  communicated  to  the  Sanitary  Department 
in  order  that  the  nuisance  may  be  abated.  Contrasted  with 
the  existing  state  of  matters  five  years  ago,  I  can  only  describe 
it  as  marvellous,  and  no  people  ought  to  be  more  grateful  to 
Professor  Ross  of  Liverpool  than  the  inhabitants  of  Durban, 
both  for  the  practical  benefits  resulting  from  his  brilliant 
researches  into  the  etiology  of  malaria,  and  for  the  effectual 
preventive  measures  he  so  simply  enunciated,  and  which  have 
been  demonstrated  and  proved  in  this  borough. 


By  MALCOLM  WATSON,  M.D.,  D.P.H. 

Chief  Medical  Officer  Estate  Hospitals  Association 
Late  Senior  District  Surgeon,  Federated  Malay  States  Medical  Service 

Abstract  by  R.  Ross 

51.  The  Prevention  of  Malaria  in  the  Federated  Malay 
States. — The  contribution  to  this  book  sent  by  Dr  Watson 
contains  a  full  and  vivid  description  of  his  enthusiastic,  large 
and  successful  campaign,  carried  out  during  the  last  nine  years. 
Unfortunately,  it  is  too  long  for  insertion  here  ;  but  owing  to  the 
interest  of  Sir  Frank  Swettenham,  G.C.M.G.,  and  a  number  of 
Rubber  Companies,  it  will  shortly  be  published  as  a  separate 
book.     I  will  here  attempt  to  give  only  a  brief  abstract. 

The  campaign  was  conducted  chiefly  in  the  State  of  Selangor. 
The  climate  is  warm  and  humid;  the  mean  rainfall  is  80'4  inches; 
and  the  country  was  originally  covered  with  thick  jungle,  and 
belonged  to  a  number  of  independent  states.  Owing,  how- 
ever, to  the  efforts  of  Sir  Frank  Swettenham,  these  states  were 
amalgamated  into  a  Federation,  since  when  there  has  been 
much  progress  in  the  country.  By  reason  of  its  products  and 
its  good  Government,  it  is  now  a  comparatively  wealthy  and 
prosperous  one.  The  history  of  malaria  prevention  in  it  dates 
from  1901,  and  is  concerned  {a)  with  prevention  in  the  towns, 
and  {b)  with  prevention  in  the  district. 

(i).  Towns. — The  two  principal  towns  are  Klang  and  Port 
Swettenham.  In  1901,  Klang,  situated  on  the  river  of  that 
name,  contained  3,576  inhabitants,  occupying  293  houses.  The 
area  of  the  town  was  about  290  acres,  of  which  22  acres  were 
swamps,  25  acres  virgin  jungle,  and  80  acres  dense  secondary 
growth,  30  to  40  feet  high.     Owing  to  the  humidity  mosquitos 

554 


Sect.  57]  PORT   SWETTENHAM  555 

bred  in  vast  numbers  all  the  }-ear  round.  During  that  year 
the  author  says  that  the  outbreak  of  malaria  reached  terrible 
proportions.  Nearly  every  one  was  attacked,  and  many  died. 
The  whole  population  was  demoralised,  and  when,  in  November, 
the  death-rate  rose  to  the  equivalent  of  an  annual  death-rate  of 
300  per  mille,  the  Chinese  suspended  business.  In  the  mean- 
time, however,  Watson  resolved  to  make  a  determined  stand 
against  the  disease,  and  after  consideration  decided  to  adopt 
my  proposals  for  mosquito  reduction.  In  this  he  was  warmly 
supported  by  Dr  E.  A.  O.  Travers,  State  Surgeon,  by  the 
Government,  the  Sanitary  Board,  and  the  people.  The  requisite 
money  was  voted  ;  the  marshes  were  rapidly  drained,  chiefly  by 
contour  drains  which  cut  off  the  inflow.  The  author  says,  "  I 
must  confess  that  I  by  no  means  expected  the  success  which  as 
a  fact  followed  the  works.  I  had  the  feeling  that  perhaps  a  20 
or  30%  reduction  might  be  obtained  in  the  hospital  returns  .  .  . 
indeed  I  was  prepared  for  a  total  failure  of  the  works.  ...  I 
record  these  feelings  that  they  may  encourage  others  who  may 
be  disinclined  by  the  apparent  magnitude  of  the  task  from 
attempting  to  combat  this  disease."  The  success  was,  however, 
complete  and  lasting. 

Port  Swettenham  is  situated  on  the  river  five  miles  from 
Klang.  It  was  founded  in  1895  in  order  to  provide  a  port  for 
ocean-going  steamers.  The  country  was  covered  with  low- 
lying  mangrove  swamp  frequently  flooded  by  the  sea.  There 
were  few  inhabitants  and  few  cases  of  malaria,  but  Watson 
observed  that  new  arrivals  quickly  became  affected.  The  place 
was  practically  a  mangrove  swamp  in  which  about  15  acres 
had  been  cleared.  On  the  15th  September  1901,  the  port  was 
formally  opened  and  the  Government  population  and  coolies 
connected  with  the  shipping  were  transferred  to  it.  Immediately 
afterwards  "  malaria  assumed  an  epidemic  character.  In  less 
than  a  month  the  180  loading  coolies  were  so  decimated  by 
disease  that  the  remainder  refused  to  live  any  longer  at  the 
port  and  returned  to  Klang."    Freshly-imported  coolies  deserted. 


556      PREVENTION    OF    MALARIA    IN    MALAY   STATES     [Sect. 

Out  of  176  Government  servants,  118  were  attacked  between 

the  loth  September  and  31st  December.     Ships  came  in  and 

could  not  discharge  their  cargoes.     The  outbreak  was  so  bad 

that  the  High  Commissioner   ordered  the  closure  of  the  port 

until    it    could    be    made    more    sanitary.       In    the    meantime 

Watson  had  recommended  measures  similar  to  those  taken  at 

Klang,  and  a  special  commission    appointed   by  Government 

adopted  them.      "  Within  six  weeks  the  work  of  the  port  was 

proceeded    with   without   great   difficulty.     An    area   of   about 

100  acres  was  bunded  and  drained  and  freed  from  jungle." 

The  results  were  immediate  and  decisive.     The  author  had 

kept  careful  hospital  statistics,  including  returns  of  all  cases  in 

individual  houses,  from  facts  known  to  him  in  his  capacity  as 

District  Surgeon.     The  figures  are  given  in  a  series  of  papers 

by  him   and   Dr  Travers  {Journal  of   Tropical  Medicine^  15th 

September,  i6th  November,  ist  December  1903,  ist  April  1905, 

2nd  July  1906).      I  attach  the  following  abstract  from  my  paper 

[1907]. 

I .  Cases  of  Malaria  admitted  to  Klang  Hospital  front  the  Two  Towns 

compared  with  those  admitted  from.  District 

Years    .         .         .         1901         1902         1903         1904         1905 

Towns  .         .         .  610  199  69  32  23 

District         .         .  197  204  150  266  353 

2.  Deaths  in  Klang  and  Port  Swettenham 

Years     •        .         1900         1901         1902         1903         1904         1905 
Fever     .         .  259  368  59  46  48  45 

Other  diseases        215  214  85  69  74  68 

3.  Deaths  registered  in  District^  excluding  Towns 

Years     .         .         1900         1901         1902         1903         1904         1905 
Fever     .         .  173  266  227  230  286  351 

Other  diseases        133  150  176  198  204  271 

4.  Infected  Children  in  Towns  and  District 
November  and  December  1904 

Klang  Port  Swettenham  District 

Children  examined     .         .         173  87  298 

Children  infected        .         .  i  i  loi 

November  and  December  1905 
Children  examined     .         .         119  76  247 


Children  infected 


59 


57]  KLANG  557 

5.  Sick  Certificates  and  Sick  Leave  Granted  to  Government  Employees 

(Numbering  176  in  1901  and  281  in  1904) 


Years    . 

1 901 

1902 

1903 

1904 

1905 

Certificates    . 

236 

40 

23 

14 

5 

Days  of  leave 

1,026 

198 

72, 

71 

30 

Since  1905  the  figures  have  not  been  accurately  kept,  but 
children  examined  at  Klang  show  evidences  of  malaria  as 
follows  : — 

1906,  out  of  142  children,     i  infected 

1907  „     „     71        ,.  3      >, 

1908  „     ,,455       >,  13      » 

1909  „     „  463       „  17      „ 

These  are  extraordinarily  small  percentages,  considering  that 
the  district  surrounding  Klang  was  not  fully  treated.  Mean- 
time, the  population  of  Klang  had  risen  to  an  estimated  total  of 
5,745.  The  results  at  Port  Swettenham  were  not  so  permanent. 
The  population  spread  into  an  undrained  area,  with  the  result 
that  there  was  an  outbreak  in  1906.  The  cause  of  this  was 
rapidly  identified  and  removed  by  drainage. 

The  cost  at  Klang  for  the  five  years  1901  to  1905  amounts 
to  $35,818  (the  Malay  dollar  appears  to  equal  2s.  4d,  British 
money).  Watson  says  that  "  much  money  was  spent  in  filling 
which  could  have  been  avoided  had  the  town  not  been  burdened 
by  the  legacy  of  its  old  brick  drains,"  and  there  was  other 
considerable  waste.  He  adds  that  the  drainage  should  have 
cost  about  £2  per  acre,  or  about  iJ^Soo  instead  of  ^3,000. 
"  Thousands  of  acres  in  the  neighbourhood  have  been  cleared 
of  malaria  at  this  cost,  and  I  can  see  no  reason  why  Klang 
could  not  have  been  similarly  dealt  with  at  a  similar  cost," 
but  of  course  many  mistakes  are  made  in  first  attempts.  At 
Port  Swettenham  the  cost  amounted  to  $52,364.  In  addition 
to  this  capital  expenditure  there  was  an  annual  one  of  ;^270 
for  maintenance  at  Klang,  and  of  ^^140  at  Port  .Swettenham. 
In  the  former  332  acres  (134  hectares),  and  in  the  latter  no 


558      PREVENTION    OF   MALARIA    IN    MALAY   STATES     [Sect. 

acres  (45  hectares)  have  been  dealt  with.  The  total  cost  was 
about  £v2  per  head  of  population  for  the  whole  five  years 
together.  The  author  says  that  in  Klang  "  not  one  single 
grain  of  quinine  was  given  to  any  of  the  population,  except 
to  those  who  were  actual  patients  from  malaria,  in  hospital 
or  in  my  official  or  private  practice."  It  should  be  observed 
that  all  this  work  was  done  before  the  species  of  carrier  had 
been  exactly  identified. 

(2).  District. — The  local  Anophelines  were  identified  by  Dr 
G.  F.  Leicester  in  his  Culicidae  of  Malaya  in  1904.  There 
are  nine  species,  of  which,  according  to  Watson,  two  are 
certainly  carriers.  One  of  these,  Mr  Newstead  tells  me,  is 
certainly  Myzorhynchus  umbrosus,  though  the  genus  is  not 
quite  certain,  and  the  other  is  Nyssorhynchus  willmori.  The 
former  breeds  all  over  the  country,  and  the  latter  only  in 
the  hilly  tracts  in  quickly  running  streams.  The  former  can 
be  entirely  removed  by  ordinary  open  drainage  channels ;  the 
latter  require  subsoil  pipe  drainage,  as  it  will  breed  with 
facility  in  the  open  channels. 

Watson's  account  of  the  extensive  malaria  campaign  in 
the  district  is  a  fascinating  one,  but  as  it  is  concerned  with 
numbers  of  scattered  rubber  plantations,  each  of  which  has 
to  be  dealt  with  separately,  the  history  is  much  too  detailed 
to  be  given  here,  though  that  history  is  an  example  of  what 
can  be  done  in  rural  areas  under  the  worst  conditions  by  all 
the  measures,  especially  by  drainage.  I  therefore  content 
myself  with  giving  his  conclusions  and  some  of  his  remarks. 
The  former  are  as  follows : — 

"(i)  That  both  flat  and  hilly  land  in  Malaya  is,  before  open- 
ing, very  malarious,  and  that  blackwater  fever  has  been  found  in 
both. 

"(2)  That  hundreds  of  square  miles  of  the  flat  land  in 
Malaya  have  been  freed  from  malaria  simply  by  draining, 
and  by  felling  the  jungle. 

"  (3)  That  the  cost  of  these  rural  anti-malaria  measures  in 


57]  CONCLUSIONS  559 

Malaya  (where  labour  is  dear)  is  about  ;^3  an  acre,  being  £2  to 
drain  and  £\  to  fell  the  heavy  virgin  jungle.  This  expenditure 
at  the  same  time  is  the  first  step  in  agriculture,  and  under  it 
the  land  has  acquired  a  considerable  increased  value. 

"(4)  That  this  freedom  from  malaria  coincides  with  the 
disappearance  of  an  Anopheline  {M.  umbrosus)  which  breeds 
in  undrained  jungle,  and  does  not  breed  in  open  earth  drains 
when  kept  clear  from  weeds,  and  flowing. 

"(5)  That  certain  hilly  land  intersected  by  ravines,  both 
open  and  drained,  is  as  malarious  as  when  first  opened. 

"(6)  That  the  continuance  of  malaria  here  is  due  to  N. 
wilhnoriy  which  breeds  in  ravine  streams,  which  cannot  be 
driven  from  them  despite  the  utmost  care  of  keeping  these 
streams  free  from  weeds,  and  which  cannot  be  completely 
washed  out  of  the  ravines  even  by  the  heaviest  tropical  showers. 

"  (7)  That  quinine  given  regularly  greatly  reduces  the  sick- 
and  death-rate  of  those  exposed  to  malaria. 

"  (8)  That  doses  of  less  than  six  grains  daily  are  of  little 
value  if  the  malaria  be  intense — say  where  the  spleen  rate  is 
75%  or  more. 

"(9)  That  when  given  in  lo-grain  doses  on  six  days  out 
of  seven,  or  in  20-grain  doses  when  a  coolie  has  fever,  or  is 
in  such  bad  health  that  he  does  not  feel  inclined  to  work, 
between  20  and  30%  of  those  taking  the  drug  will  still  be 
found  with  parasites  in  their  peripheral  blood. 

"(10)  That  the  use  of  quinine  can  therefore  never  result  in 
the  abolition  of  malaria,  or  even  make  any  material  reduction 
in  the  liability  to  infection  in  a  malarious  ^  locality. 

"(11)  That  mosquito-proof  houses  have  a  value;  but  the 
attempt  to  discover  a  satisfactory  mosquito-proof  coolie  house 
ended  as  an  inconclusive  experiment. 

"(12)  That  not  only  for  urban,  but  for  rural  districts,  anti- 
malaria  sanitation  should  be  based  on  mosquito  reduction,  if 
this  be  a  physical  possibility." 

^  ?  Intensely  malarious. — R.  Ross. 


56o      PREVENTION   OF   MALARIA   IN    MALAY   STATES    [Sect. 

The  author  has  many  additional  remarks  to  make,  of  which 

1  here  note  the  following  : — 

(i)  There  was  conclusive  evidence  that  the  construction  of 
roads  increases  the  malaria  in  Malaya  by  obstructing  drainage. 

(2)  In  the  flat  land  removal  of  jungle  within  a  radius  of 
about  half  a  mile  from  plantations  suffices  to  remove  malaria, 
as  proved  by  many  experiences  over  a  distance  of  about 
50  miles,  but  this  does  not  suffice  in  the  hilly  land,  where 
malaria  is  carried  by  Nyssorhynchiis  wilbnori. 

(3)  As  shown  by  examination  of  large  numbers  of  children, 
proximity  to  jungle  greatly  increases  the  malaria  rate. 

(4)  He  says,  "  We  never  seem  to  hear  that  a  place  always 
remains  unhealthy,  and  never  improves  as  time  goes  on.  This 
is  because,  after  a  time,  the  population  of  an  unhealthy  place 
consists  almost  entirely  of  those  who  have  acquired  a  certain 
amount  of  immunity.  New  people  have  practically  ceased 
to  come  to  it,  and  so  the  health  seems  to  improve.  But  it 
only  wants  new  arrivals  to  come  in  numbers  to  start  a  severe 
epidemic  of  malaria." 

(5)  The  introduction  of  a  large  number  of  Tamil  coolies  has 
greatly  increased  the  malaria  rate  in  certain  plantations.  This 
is  due  to  the  principles  laid  down  in  section  30  (17  and  18). 

(6)  Regarding  quinine  prevention,  he  makes  the  following 
further  remarks.  On  one  estate  fifty-six  coolies  were  found 
to  have  parasites,  though  they  were  getting  6  to  8  grains  of 
quinine,  with  double  doses  when  they  were  ill.  Of  these  75% 
were  apparently  in  the  most  perfect  health,  while  87%  were  in 
good  health  and  fit  for  work.  The  author  says  that  this  "  clearly 
demonstrated  that,  while  keeping  the  malaria  in  check,  so  that 
the  coolies  can  carry  on  their  work,  three  years'  administration 
of  the  drug  had  entirely  failed  to  eradicate  the  disease.  That 
the  estate  is  really  as  unhealthy  as  ever  is  shown  by  the  visitors 
to  it  who  contract  malaria  in  about  ten  days  .  .  .  finally,  out 
of  19  N.  willmori  captured  in  the  lines,  4,  or  21^,  had  malaria, 

2  with  zygotes,   i   with   sporozoits    and    i   with   both   zygotes 


57]  QUININE   AND    DRAINAGE  561 

and  sporozoits."  The  author  further  examined  an  estate  in 
which  10  grains  of  quinine  were  given  in  the  most  thorough 
and  systematic  manner  to  each  adult  who  worked,  and  20  grains 
to  those  who  did  not  work,  and  5  grains  daily  to  children,  with 
double  doses  when  they  were  ill.  The  blood  of  29  children 
was  examined,  and  the  parasites  were  found  in  276%  of  these ; 
while  out  of  125  adults  the  parasites  were  found  in  18-4%,  giving 
a  total  of  20%  infected  out  of  1 54  persons.  The  author  observes 
that  quinine  has  little  effect  on  the  gametids ;  that  patients 
die  even  after  40  grains  of  quinine  daily,  and  repeats  my  teaching 
regarding  the  persistence  of  the  sporids  (Chapter  IV) ;  but  adds  : 
"  If,  as  has  been  shown,  the  immunity  from  malaria  produced 
by  quinine  leaves  the  patient  infective  while  he  is  acquiring  the 
immunity,  then  it  will  be  impossible,  in  the  presence  of  many 
Anophelines,  and  in  the  presence  of  many  new  arrivals  (such 
as  newly-born  children),  ever  to  eradicate  malaria  by  quinine. 
It  follows,  too,  that  if  drainage  be  an  alternative,  even  though 
much  more  expensive,  drainage  must  be  the  method  which 
should  be  adopted.  Even  if  the  community  possesses  no  money 
for  drainage,  money  might  be  borrowed  with  which  to  carry 
out  the  works,  and  at  the  end  there  would  be  an  asset  to  show 
for  the  expenditure.  Borrowing,  however,  would  be  impossible 
if  the  object  were  to  buy  quinine.  It  must  not  be  forgotten, 
too,  that  the  administration  of  quinine  in  effective  doses  is  by 
no  means  an  inexpensive  method.  To  give  10  grains  daily  to 
one  thousand  people,  without  any  extra  to  those  who  actually 
have  pyrexia,  for  ten  years  would  cost  about  ;!^i,900.  Such 
a  sum,  if  lent  by  a  government  to  a  community  at  a  reason- 
able rate  of  interest,  would  free  a  very  large  area  from  malaria 
if  drainage  methods  suitable  to  the  local  Anophelines  were 
employed.  And  in  ten  years  the  community  would  have  nine 
years  of  prosperity  and  health  in  which  to  repay  the  loan.  In 
the  case  of  many  small  villages,  it  would  probably  be  possible 
to  eradicate  the  breeding-places  of  Anophelines,  where  they 
are  in  the  midst  of  the  community,  at  a  mere  fraction  of  the 

2  N 


562     PREVENTION  OF  MALARIA  IN  MALAY  STATES    [Sect.  57 

money  which  would  be  required  to  dose  the  population  effec- 
tively with  quinine,  even  for  a  year.  While  for  other  com- 
munities the  cost  of  drainage  would  be  relatively  much  less 
than  in  the  case  of  the  smaller  ones,  since  the  same  expenditure 
would  protect  a  relatively  larger  number  of  people  "  (section  39). 

(7)  The  author  carefully  compares  the  conditions  in  Italy 
with  those  in  his  country.  The  reason  for  the  freedom  of  the 
hills  in  Italy  from  malaria  is  that  the  principal  carrier  there 
is  a  pool  breeder  and  not  a  stream  breeder.  The  attitude  of 
the  Italians  to  quinine  is  due  to  local  conditions,  drainage  being 
difficult  in  many  malarious  localities  there,  especially  along 
the  coast.  But  as  regards  the  tropics,  the  author  adds  :  "  To  me 
it  seems  only  the  vision  of  a  dream  that  any  organisation  will 
ever  induce  a  whole  tropical  population  to  take  quinine  in  the 
doses  required  by  the  Italians.  And  when  it  is  further  con- 
sidered that  the  population,  even  when  taking  this  quinine, 
would  still  be  infectious,  the  policy  of  spending  money  on 
quinine  for  an  indigenous  population,  where  drainage  is  possible, 
appears  to  me  indefensible  either  on  medical  or  financial 
grounds"  (section  39). 

(8)  The  author  also  discusses  malaria  in  India,  and  criticises 
the  statements  of  James  and  Christophers  {^Lancet,  20th  June 
1909).  He  does  not  agree  with  them  that  "prevalence  of 
Anophelines,  though  always  important,  is  by  no  means  in  every 
case  the  most  important  factor  to  be  considered,"  or  that  the 
Italian  measures  are  most  suitable  in  India.  He  states  that 
the  Malayan  experiences  should  apply  also  to  India,  and  adds  : 
"  The  logical  conclusion  therefore  seems  to  me  that  quinine  can 
never  do  more  than  give  a  temporary  relief  to  India,  and  that 
the  factor  to  be  dealt  with  is  the  Anopheles^  and  that  measures 
must  be  aimed  at  it — not  only  in  towns,  but  also  in  rural 
districts."     For  N.  willmori  he  advises  closed  subsoil  drains. 


By  Dr  T.  TAKAKI 

Director  of  the  Medical  School,  Chief  of  the  Sanitary  Bureau, 
Government  of  Formosa 

58.  Prevention  of  Malaria  in  Formosa.— (i).  Brief  sketch  oj 
Formosa. — The  island  of  Formosa,  which  came  under  Japanese 
rule  in  1895,  lies  between  Lat.  21°  45"  and  Lat.  25°  37"  N.,  and 
between  Long.  119°  18"  and  122'^  6"  E.,  comprising  an  estimated 
area  of  13,434  square  miles.  The  following  are  the  numbers 
of  the  population,  according  to  the  latest  investigation : — 

Formosans 3>036,855 

Aborigines         ........  120,254 

Japanese            ........  83,229 

Foreigners  (including  Chinese)        .         .         .         .  12,151 


Total  Deaths. 

Per  1000. 

104,622 

100-9 

102,853 

111-9 

102,232 

114-5 

Total  population 3,225,589 

Malaria  prevails  over  nearly  all  localities  of  the  island,  and 
the  deaths  caused  by  malaria  in  1906- 1908  are  given  below. 

^  Deaths 

''^^''-  from  Malaria. 

1906  10,562 

1907  iijOiS 

1908  11,714 

Statistics  only  for  the  years  1906- 1908  are  given  above,  no 
available  ones  being  obtainable  for  the  preceding  years. 

It  must  be  remembered  that  there  are  still  about  1,800  native 
practitioners  of  the  Chinese  school  in  the  island,  whose  service 
is  scarcely  to  be  depended  upon. 

\2).  Mosquitos  which  carry  the  parasites. — Seven  species  of 

563 


(2) 

An. 

(3) 

An. 

(4) 

An. 

(5) 

An. 

(6) 

An. 

(7) 

An. 

(8) 

An. 

564  PREVENTION    OF    MALARIA   IN    FORMOSA         [Sect. 

Anophelina  are  known  to  be  in  existence  in  Formosa,  with  an 
additional  one  recently  discovered  ;  they  are  as  follows  : — 

(i)        Anopheles         {Myzorhynchus)  sinensis  Wied. 

{Myzomyia)  listoni  Liston. 

{Mj/z.)  rossii  Giles. 

(Myz.)  species,  from  Taito. 

{Nyssorhynchus)  annulipes  Walk. 

{Nys^  maculatus  Theobald. 

{^Nys.)  fuliginosus  Giles. 

{Cellid)  kocJii  Donitz. 

Of  these,  the  first  two  species  have  been  found  to  be  the 
medium  of  malaria.  According  to  the  announced  result  of 
experiments  made  by  the  late  Dr  Kinoshita  and  Dr  Miyajima 
and  others,  Anopheles  sinensis  has  the  power  of  developing  the 
Plasmodium  vivax  of  tertian  fever,  but  not  the  Plasmodium, 
praecox  of  aestivo-autumnal  fever  ;  while  Anopheles  listoni  is 
host  of  PI  praecox,  its  cysts  growing  upon  the  mosquitos' 
intestinal  wall.  In  other  words,  tertian  fever  is  transmitted 
by  Anopheles  sinensis,  and  aestivo-autumnal  fever  by  An.  listoni. 
Anopheles  rossii  being  recognised  as  an  innoxious  species,  no 
cyst  of  Plasmodium  can  be  found  growing  in  its  body  by 
process  of  infecting  experiments.  The  pathogenical  importance 
of  other  Anophelines  are  not  yet  clearly  defined. 

In  the  order  of  the  extent  of  prevalence.  Anopheles  sinensis^ 
the  tertian  fever  carrier,  comes  first ;  and  next  comes  An.  listoni^ 
a  much  smaller  but  extremely  dangerous  species.  An.  rossii 
is  mostly  found  in  the  middle  and  south  of  Formosa,  its  sphere 
of  influence  in  the  north  being  limited  to  24°  N.  The  newly- 
discovered  Anopheles  from  Taito  (on  the  east  coast)  was  like- 
wise collected  in  the  southern  part.  The  remaining  three 
species  of  Nyssorhynchus  are  met  with  in  the  mountainous 
districts.  The  newly- discovered  An.  kochi  has  been  obtained 
in  Keelung,  which  lies  18  miles  north  of  Taihoku. 


S8] 


MEASURES   AND    RESULTS 


565 


(3)    Preventive  measures  adopted. — 

A.  By  the  general  improvement  of  sanitary  conditions  in 

towns  and  in  the  country,  as,  for  instance,  by  the 
construction  of  properly  macadamised  and  paved 
roads,  the  discontinuance  of  the  use  of  the  drink- 
ing-water mixed  with  sewage,  the  facilitating  of  the 
carrying  off  of  rain-water  and  drainage,  and  so  on. 

B.  Protection    from  mosquito  attacks  by  means  of  wire- 

gauzed  shutters  and  windows,  and  mosquito-nets, 
etc.,  etc.  This  means  is  chiefly  adopted  by  the 
garrison  troops  here. 

C.  Prophylactic  administration  of  quinine  after  R.  Koch. 

D.  Thoroughgoing  post-malarial  treatment. 

(4).  Results. — As  a  marked  result  of  the  above-mentioned 
public  measure  A.,  Taihoku  and  Taichu,  which  formerly  used 
to  be  malaria-stricken  places,  are  now  found  completely  cleared 
of  the  dreaded  disease.  As  to  the  merit  of  the  mechanical 
measure  B.^  reference  may  be  made  to  the  uniformly  improved 
health  condition  among  the  troops  of  Formosa.  The  measure 
of  screening  the  barrack  windows,  etc.,  with  wire-gauze  was 
first  resorted  to  by  the  garrison  here  in  the  summer  of  1909. 

The  following  Table  shows  its  result : — 


TABLE 

I. 

Year. 

Malaria  cases 

Malaria  deaths 

per  1,000  soldiers. 

per  r.ooo  soldiers. 

1897 

2724-3 

17-3 

1898 

2493-9 

19-3 

1899 

235 1 '0 

23-9 

1900 

2345'5 

20-7 

1901 

1768-2 

II-5 

1902 

1 1427 

7-1 

1903 

4608 

1-7 

1904 

213-8 

i-i 

1 90s 

145-0 

3-1 

1906 

280-3 

2-1 

1907 

528-1 

2-1 

1908 

498-3 

13 

566  PREVENTION    OF   MALARIA   IN    FORMOSA         [Sect. 

The  unusual  increase  of  the  number  of  malaria-affected 
soldiers  in  the  last  year  is  accounted  for  by  the  fact  that  in 
the  said  year  many  soldiers  fell  victims  to  malaria  during  the 
big  campaign  against  the  savages,  and  that  the  sick  -  rate 
adopted  by  the  Army  was  rather  too  high. 

As  a  result  of  the  medicinal  measure  C,  the  experiment 
made  at  Kosenpo  may  profitably  be  referred  to. 

Kosenpo  is  a  village  lying  in  the  southern  mountainous 
districts,  the  majority  of  whose  inhabitants  are  camphor 
collectors. 

In  April  1907  malaria  prevailed  terribly  in  this  locality, 
especially  among  Japanese  new-comers,  so  that  30^  of  the 
Japanese  residents  proved  to  be  malaria  patients.  From  July 
1907  R.  Koch's  gramme-prophylaxis  began  to  be  systematically 
used  under  the  direction  of  the  late  Dr  Kinoshita.  The  people 
were  administered  quinine  hydrochlorate  in  pastil,  in  pro  dosi 
vo  for  adult,  every  nine  and  ten  days  successively.  The  pro- 
phylaxis was  strictly  conducted  under  care  of  the  police  officials 
from  July  to  November  1907,  and  from  January  to  October  1908. 
The  reduction  of  both  malaria-morbidity  and  malaria-mortality 
will  clearly  be  seen  from  the  following  Table  II. 

(5).  Estimated  cost  incur-red  for  the  prevention  of  malaria. — 
No  estimated  costs  for  the  prevention  of  malaria  can  be  given, 
as  they  differ  according  to  various  circumstances. 

Note  by  R.  Ross.— By  the  kindness  of  Professor  Dr  Kitasato,  Dr  M. 
Miyajima  of  his  Institute  for  Infectious  Diseases  at  Tokio  has  suppHed  me 
with  the  malaria  statistics  of  the  Imperial  Japanese  Army,  serving  in  Japan, 
China,  Chorea  and  Manchuria,  as  given  by  the  Medical  Bureau  of  the 
Army.     The  totals  for  three  years  are  as  follows  : — 

Years.      Total  Patients.     Total  Deaths.     Malaria  Patients.     Malaria  Deaths, 

1906  77,lc>o       749        2,717  10 

1907  104,266       636        4,863  9 

1908  114,794       646        4,666  7 


296,060  2,631  12,246  26 

Dr  Miyajima  says  that  in  Japan  itself  the  parasite  is  almost  exclusively 
P.  vivax,  but  that  the  other  species  occur  in  Formosa  and  the  Loo  Choo 
Islands.  The  largest  number  of  malaria  cases  were  in  Formosa  and  in 
Chorea  (5,348  and  1,974  cases  respectively  in  the  three  years). 


58] 


RESULTS 
TABLE   II. 


567 


A/TnntVi 

Japanese 

Malaria 

Malaria 

Malaria  cases 

Malaria  deaths 

IVi  (J  1 1 L  i  1  ■ 

Inhabitants. 

cases. 

deaths. 

per  1,000  Japanese. 

per  1,000  Japanese. 

1906 

Jan. 

314 

Unknown 

Unknown 

Feb. 

211 

51 

I 

265-4 

4-74 

March 

387 

105 

I 

271-3 

2-58 

April 

502 

165 

I 

328-7 

1-99 

May 

741 

256 

2 

345-5 

2-70 

June 

754 

394 

I 

522-5 

1-33 

July 

836 

408 

7 

488-0 

8-37 

Aug. 

1,006 

593 

9 

589-5 

8-95 

Sept. 

984 

503 

12 

5II-2 

I2-20 

Oct. 

1,094 

659 

6 

602-4 

■5-48 

Nov. 

1,229 

579 

14 

471-1 

11-39 

Dec. 

1,364 
Average  Population 

496 

5 

363-6 

3-67 

Total 

785-2 

4,209 

59 

5,361-8 

75-14 

1907 

Jan. 

1,494 

329 

I 

220-2 

067 

Feb. 

1,435 

244 

I 

170-0 

0-70 

March 

1,508 

172 

3 

II4-I 

1-99 

April 

1,626 

220 

0 

135-3 

0 

May 

1,708 

243 

I 

142-3 

0-59 

June 

1,806 

274 

2 

I5I-7 

i-ii 

* 

July 

1,487 

208 

I 

139-9 

0-67 

* 

Aug. 

1,588 

141 

2 

88-8 

1-26 

* 

Sept. 

1,604 

76 

I 

47-4 

0-62 

* 

Oct. 

1,625 

46 

I 

28-3 

0-62 

* 

Nov. 

1,668 

75 

2 

45-0 

1-20 

Dec. 

1,665 

Average  Population 

116 

2 

69-7 

1-20 

Total 

I,6oi-2 

2,144 

17 

1,338-1 

10-61 

1908* 

Jan. 

1,669 

102 

0 

6ri 

0 

* 

Feb. 

1,668 

60 

I 

36-0 

060 

* 

March 

1,675 

44 

0 

26-3 

0 

* 

April 

1,674 

58 

0 

34-6 

0 

* 

May 

1,883 

92 

0 

48-9 

0 

* 

June 

1,918 

127 

0 

66-2 

0 

* 

July 

1,898 

169 

0 

89-0 

0 

* 

Aug. 

1,933 

152 

0 

78-6 

0 

■x- 

Sept. 

1,949 

168 

2 

86-2 

1-03 

* 

Oct. 

1,829 

183 

2 

lOO'I 

1-09 

Nov. 

1,282 

169 

3 

I3I-8 

2-32 

Dec. 

1,258 
Average  Population 

143 

I 

113-7 

0-79 

Total 

1,719-2 

1,467 

9 

8i8-2 

5-23 

(*  indicate  prophylacted  months.) 


By  RONALD  ROSS,  D.P.H.,  F.R.C.S.,  D.Sc,  LL.D., 

F.R.S.,  C.B. 

Major  Ind.  Med.  Serv.  {t-et.) 

President,  Society  of  Tropical  Medicine  and  Hygiene ;  Professor  of 
Tropical  Medicine,  University  of  Liverpool  and  Liverpool  School  of 
Tropical  Medicine 

59.  Notes  on  Some  Other  Works. —  It  is  impossible  to  give 
within  the  limits  of  this  book  a  full  account  of  all  the  campaigns 
which  have  been  commenced,  or  even  to  mention  some  of  them  ; 
but  I  think  that  brief  notes  on  the  following  works  should  be 
added. 

(i).  India. — In  section  7  I  described  my  own  work  in  India 
up  to  the  publication  of  a  report  [1899]  in  which  I  suggested 
my  proposals  for  mosquito  reduction.  By  this  time  I  had  left 
India ;  and  no  notice  was  taken  of  the  report,  except  that 
several  medical  men  wrote  against  the  idea.  They  pointed  out 
that  Anophelines  breed  in  rice-fields,  and  so  on,  near  canton- 
ments, and  therefore  thought  that  the  task  of  banishing  them 
would  be  impossible.  They  evidently  failed  to  understand  my 
arguments,  and  had  no  idea  of  the  economical  principle  laid 
down  in  axiom  3  of  section  38. 

At  this  time  many  persons  were  writing  up  the  recent 
discoveries.  Unfortunately,  some  of  them  were  not  personally 
acquainted  with  the  tropics,  and  few  of  them  had  any  know- 
ledge whatever  of  practical  tropical  sanitation.  It  was  almost 
impossible  to  make  them  understand  my  proposals ;  but  some 
of  them  clamoured  for  a  formal  experiment  to  test  them  in 
the  field.  I  was  very  averse  from  this  suggestion.  Success 
would  demand  a  long  and  patient  enquiry,  requiring  an  exact 
preliminary  survey  of  the  amount  of  malaria  and  the  number 
of  mosquitos  present,  followed  by  equally  exact  measurements 
of  these  quantities   made  on  frequent  occasions.     Now  it  will 

be  seen  from  Chapter  V  how  difficult  it  is  to  measure  malaria 

568 


Sect.  59]  INDIA  569 

exactly,  and  how  much  more  difficult  to  obtain  any  direct 
enumeration  of  the  Anophelines.  Moreover,  failure  might  be 
due,  not  only  to  the  impracticability  of  my  proposals,  but 
also  to  want  of  enthusiasm  or  care  in  those  who  were  appointed 
to  test  them.  Thus  failure,  or  at  least  an  indecisive  result, 
was  very  probable,  and  would  have  a  disastrous  effect  upon 
anti-malaria  work  for  many  years.  I  thought  it  would  be 
much  better  to  allow  local  authorities  to  attempt  the  work 
quietly  in  the  ordinary  course  of  sanitation,  and  not  as  a  formal 
test  experiment ;  and  this  was  actually  done  since  1902  in 
Havana,  Ismailia,  the  Federated  Malay  States,  and  elsewhere. 

But  my  critics  could  not  be  got  to  understand  the  bad 
policy  of  their  suggestions,  and  consequently  the  so-called  test 
experiment  was  commenced  at  Mian  Mir,  near  Lahore,  Punjab, 
India.  The  place  was  a  most  unsuitable  one ;  almost  flat,  with 
an  impervious  subsoil  and  watered  by  irrigation,  mosquito 
reduction  was  not  easy  in  it.  Moreover,  it  was  a  military 
cantonment  containing  scattered  barracks,  from  which  statistics 
of  the  local  malaria  rate  could  hardly  be  compiled,  since  the 
troops  and  their  followers  were  frequently  being  changed  from 
other  stations ;  while,  lastly,  the  place  was  scarcely  a  town, 
that  is,  a  locality  which  was  most  appropriate  for  mosquito 
reduction.  In  fact,  the  selection  of  the  place  showed  how 
little  the  subject  was  understood  at  that  time. 

Mian  Mir  was  examined  by  the  Malaria  Commission  of  the 
Royal  Society  in  1901,  but  without  any  exact  estimates  of  the 
amount  of  malaria  or  the  number  of  Anophelines.  In  April 
1902,  however,  practical  operations  were  at  once  commenced, 
evidently  on  the  model  of  my  suggestions  for  Sierra  Leone, 
and  were  continued  for  that  and  the  following  year.  For  1902 
the  operations  were  reported  upon  by  S.  P.  James  [1903],  and 
for  the  following  year  by  S.  R.  Christophers  [1904].  The 
former  reported  very  doubtful  success,  and  the  latter  practically 
denied  the  feasibility  of  mosquito  reduction.  Their  reports 
were,   however,  exhaustively   criticised    by  myself  in  a  paper 


570  NOTES   ON   SOME   OTHER  WORKS  [Sect. 

[1904],  to  which  no  reply  has  been  given;  and  also  by  Sewell 
[1904],  Giles  [1904],  and  others. 

No  one  who  is  acquainted  with  the  nature  of  scientific 
evidence  can  imagine  for  a  moment  that  this  experiment 
gave  any  proof  of  anything  connected  with  the  subject.  The 
measurements  of  malaria  were  of  the  most  inadequate  nature, 
and  were  based  upon  the  most  insufficient  random  sampling 
— while  in  some  cases  the  number  of  children  examined  was 
not  recorded  (section  31  (8)).  The  enumeration  of  mosquitos 
was  evidently  of  an  equally  casual  nature,  the  authors  not 
having  been  able  to  devise  any  accurate  method.  Neither 
report  was  well  written,  and  the  second  one  was  worded  so 
confusedly  that  almost  anything  might  be  inferred  from  it. 
Both  reports  claimed  that  the  mosquitos  increased  in  spite  of 
the  reduction  measures.  This  is,  of  course,  possible  to  a  certain 
extent  (section  29  (8)) ;  but  it  is  otherwise  mathematically 
impossible,  and  the  statement  suggests  only  that  the  authors' 
methods  were  inaccurate.  As  no  exact  enumeration  of  the 
mosquitos  had  been  made  before  the  operations,  the  total 
result  of  the  work  could  not  be  determined.  In  fact  the  reader 
who  is  interested  in  exact  work  will  do  well  to  compare  these 
reports  with  Chapter  VI,  if  only  to  learn  what  not  to  do  as 
regards  the  measurement  of  malaria  and  of  mosquitos,  and 
the  conduct  of  a  campaign. 

It  has  been  frequently  claimed  by  several  Indian  writers  on 
the  prevention  of  malaria,  that  the  operations  at  Mian  Mir 
were  carried  out  merely  to  determine  the  practical  feasibility 
of  mosquito  reduction  for  a  reasonable  cost  in  India.  Even 
this  claim  cannot  be  accepted.  During  the  first  year  (1902) 
only  7,216  rupees  were  expended  for  dealing  with  an  area  of 
4  square  miles  containing  numbers  of  troops,  and  of  this  sum, 
5,364  rupees  were  spent  on  bricking,  lining  and  plastering  a 
single  watercourse,  leaving  only  1,851  rupees,  or  about  £120 
for  the  rest  of  the  work.  This  is  hardly  a  convincing  ex- 
penditure for  a  test  experiment.     The  life  of  a  single  soldier 


59]  INDIA  571 

costs  more.  It  will  scarcely  be  believed  that  in  the  second 
report  of  the  experiment,  designed,  as  has  been  declared,  for 
the  express  purpose  of  providing  official  information  for  the 
whole  of  India,  no  accounts  whatever  of  the  cost  incurred  were 
vouchsafed !  In  fact,  the  whole  affair  was  conducted  on  un- 
practical and  unscientific  lines.  It  proved  nothing  at  all,  and 
its  only  effect  was  to  retard  anti-malaria  work  in  that  and 
other  countries  for  years. 

Since  1904  the  military  authorities  at  Mian  Mir  undertook 
much  more  patient  and  useful  work  there,  with  the  apparent 
result  of  a  considerable  reduction  in  malaria  —  see  especially 
H.  D.  Rowan  [1908].  At  the  Bombay  Medical  Congress  of 
1909,  however,  S.  P.  James  described  how,  during  a  recent 
visit  to  Mian  Mir,  he  had  found  no  reduction,  either  in  the 
malaria  or  in  the  number  of  mosquitos.  His  statements  were 
immediately  controverted  by  five  administrative  medical  officers 
(see  Lancet,  3rd  July  1909).  James  stated  that  out  of  ten  men 
of  the  Gloucester  regiment,  who  had  been  taking  quinine 
regularly,  and  who  were  selected  by  him  at  Mian  Mir  "  more 
or  less  at  random,"  he  found  parasites  in  no  less  than  eight — 
an  enormous  percentage.  The  commandant  of  the  regiment, 
however,  informed  me  at  Bombay  shortly  afterwards  that  his 
regiment  had  not  suffered  much  from  malaria  at  that  time. 

Many  local  campaigns  have  been  commenced  in  India,  and 
will  be  found  mentioned  in  the  Annual  Sanitary  Reports,  in 
the  Proceedings  of  the  Malaria  Conference  [1910],  and  in  a  recent 
publication  by  W.  G.  King  [1909],  and  elsewhere.  I  have 
received  many  private  communications  regarding  these,  from 
which  I  gather  that  they  have  not  been  given  much  encourage- 
ment from  headquarters,  that  the  organisation  has  not  been 
sufficient  to  ensure  continuity,  and  that  the  necessary  measure- 
ments of  malaria  have  been  quite  inadequate.  There  is  no 
doubt  that  the  general  policy  of  a  clique  in  India  has 
been  opposed  to  mosquito  reduction,  and  has  not  been  very 
keenly  interested  in  any  other  form  of  malaria  campaign.     A 


572  NOTES   ON   SOME   OTHER  WORKS  [Sect. 

party  in  that  country  has  been  advocating  quinine  on  the 
Italian  model,  and  appears  to  have  persuaded  the  Government 
that  it  will  cost  nothing,  while  mosquito  reduction  must  always 
be  enormously  expensive.  Personally,  I  would  welcome  any 
measure  that  is  effective,  but  apparently  not  even  the  quinine 
method  has  been  fully  pushed  in  that  country.  Experience 
will,  I  think,  prove  to  the  Government  of  India  that  no 
anti  -  malaria  campaign  can  be  conducted  without  expense ; 
that  each  measure  has  its  proper  sphere  of  action ;  and  that 
quinine  may  not  always  cost  less  than  other  measures.  Up 
to  the  present  the  work  in  India  seems  to  me  to  have  been 
wanting  both  in  intelligence  and  in  leadership,  in  spite  of  the 
1,000,000  deaths  a  year  officially  attributed  to  malaria  there. 
In  October  1909  an  Imperial  Malaria  Conference  was  held 
at  Simla.  It  was  not,  I  think,  arranged  in  a  perfectly 
satisfactory  way.  Engineers  and  several  good  workers  on 
the  subject  appear  not  to  have  been  called.  Nevertheless,  the 
conclusions  of  the  Conference  simply  confirmed  my  proposals, 
especially  as  put  in  my  Mauritius  report.  I  hope  that  the 
Conference  will  mark  the  beginning  of  a  new  era  in  India. 

C.  A.  Bentley  has  recently  published  a  report  on  malaria 
in  Bombay  [19 10].  A.  G.  M'Kendrick  had  found  a  splenic 
index  of  629/8325  =  7*5%,  and  the  author  one  of  3075/21,517  = 
I4"3//.  The  local  carrier  is  Nyssorhynchus  stephensi,  which, 
unlike  most  Anophelines,  breeds  readily  in  deep  wells,  cesspits, 
cisterns  and  salt  water.  The  author  recommends  a  campaign 
against  it  (not  including  other  mosquitos)  chiefly  by  means 
of  strict  legislation  aimed  at  the  removal  or  protection  of 
such  waters  by  householders,  and  does  not  appear  to  advocate 
any  special  municipal  organisation.  Such  legislation  is  certainly 
a  necessary  preliminary  and  easy  to  suggest ;  but  in  practice 
the  cost  of  the  numerous  inspections  and  summonses  required 
to  enforce  it  is  apt  to  exceed  that  of  doing  the  work  by 
departmental  agency,  as  hygienists  well  know  (axioms  6  and 
7,  section  38).     Nevertheless,  municipalities  like  the  idea,  because 


59]  HONGKONG  573 

it  appears  at  first  sight  to  put  them  to  no  expense.  We 
generally  observe  two  things  about  tropical  municipalities — 
the  excellence  of  their  sanitary  laws  and  the  completeness 
with  which  the  public  ignores  them.  Which  is  the  cheaper 
in  the  end,  {a)  to  make  one  inspection  and  then  do  the  work, 
or  {b)  to  make  many  inspections,  worry  the  householder,  issue 
several  summonses,  be  finally  forced  to  do  the  work,  and  then 
try  to  recover  the  cost  in  the  law  courts?  We  must  always 
remember  this  question,  and  endeavour  to  arrange  a  proper 
balance  between  the  respective  obligations  of  the  householder 
and  the  municipality. 

(2).  Hongkong.  —  One  of  the  earliest  and  best  of  the 
campaigns  in  British  territory.  The  city  of  Victoria,  usually 
called  Hongkong,  runs  for  nearly  5  miles  along  the  north  of 
the  island  of  that  name  at  the  mouth  of  the  Canton  river  in 
South-East  China.  The  island,  1 1  miles  long  and  from  2  to 
5  miles  broad,  consists  of  a  broken  ridge  of  hills,  rising  to 
nearly  2,000  feet,  and  the  city  is  built  on  a  hill  sloping  down 
to  the  water,  some  of  the  terraces  and  houses  being  500  feet 
above  sea-level.  There  is  also  a  large  residential  district  on 
the  mountains  reached  by  a  cable  tramway.  The  soil  is 
crranitic.  All  along-  the  face  of  the  hill  on  which  Victoria  is 
built  there  are  beds  of  streams,  known  as  "  nullas,"  which 
used  to  swarm  with  Anopheline  larvae.  The  population  of 
the  colony  was  377,850  in  1905,  of  which  10,835  were  whites 
(nearly  half  belonging  to  the  British  Army  and  Navy).  The 
rainfall  is  from  70  to  80  inches  a  year.  Malaria  has  been 
always  very  prevalent  here,  and  I  remember  that  in  1881  the 
colony  was  cited  as  an  example  of  the  telluric  miasma  due 
to  decaying  granite.  The  first  researches  on  the  new  lines 
were  commenced  as  early  as  May  1901  by  Dr  J.  C.  Thomson 
[1901],  who  undertook  an  exhaustive  study  of  the  mosquitos 
and  their  breeding-places.  He  examined  over  32,000  specimens, 
of  which  he  found  about  4^  to  be  Anophelines,  and  in 
November  advised  an  active  anti-malaria  campaign  by  drainage, 


574  NOTES   ON   SOME   OTHER  WORKS  [Sect. 

clearing  of  jungle,  "training"  of  the  nullas,  the  use  of  wire- 
gauze,  oiling  pools,  and  quinine  prophylaxis.  As  seen  by  his 
excellent  papers  [1900- 1903],  his  recommendations  were  not  of 
a  general  nature,  but  were  particular,  practical  and  exact. 
These  recommendations  were  rapidly  acted  upon  by  the 
Government.  Since  1901  all  the  nullas  or  watercourses  within 
and  near  the  city  were  "  trained  " — that  is,  rendered  so  smooth 
and  even  that  the  Anophelines  could  no  longer  breed  in  them ; 
and  much  similar  work  was  done  wherever  most  needed  else- 
where by  training  watercourses,  buying  up  rice-fields,  and  so 
on.  The  details  of  the  campaign  are  so  numerous  that  it  is 
impossible  to  give  them  here.  They  will  be  found  in  the 
publications  given  in  the  bibliography  and  in  a  good  paper 
by  Mr  J.  M.  Young  [1901],  who  took  part  in  the  early  stages 
of  the  work.  The  results  are  given  in  the  annual  sanitary 
reports  of  the  colony,  and  in  a  recent  address  by  the  medical 
officer  of  health,  Dr  Francis  Clark  [1906].  Dr  Thomson  informs 
me  that  before  estimating  them  it  is  necessary  to  remember 
that  malaria  can  never  become  extinct  in  Hongkong  owing 
to  the  fact  that  some  three  thousand  to  four  thousand  natives 
come  and  go  from  and  to  the  country  districts  every  day,  and 
that  a  number  of  these  will  remain  infected  in  spite  of  all 
local  measures.  Nevertheless,  the  figures  show  a  rapid  diminu- 
tion both  in  the  admission  and  in  the  death-rates. 

Malaria  Statistics  in  two  large  Hospitals 

Years          .     1897     1898     1899     1900     1901     1902     1903  1904  1905 

Admissions     1021       865       780    1,220    1,294       752       568  433  419 

Deaths       .       197       126         63       163       132       128         63  58  54 

Admission  Rate  of  Police  for  Malaria 

Years         .         .  1896  1897   1898  1899  1900  1901    1902   1903  1904  1905 
Admissions  %    .     32  "'^^  25       19       31       42      44       19       18       11       12 

Deaths  from  Malaria 

Years  .         .      1896     1897  1898   1899   1900  1901    1902   1903   1904     1905 

Population         .  239,419  377,850 

Total  deaths      .      533       554  530     546     555     574     425     300     301       285 
Deaths    in    city 

(Chinese  only)       290       302  280     218     242     281      189     152       90         87 


59]  CANDIA  575 

The  official  sanitary  reports  give  similar  figures.  The 
improvements  have,  of  course,  varied  much  in  different  localities. 
Thus  in  1900  the  western  end  of  Bonham  Road  used  to  be 
one  of  the  worst  districts.  Now,  in  1905,  it  is  reported  not  to 
have  sent  a  single  case  to  the  Government  Civil  Hospital 
[1900-1905]. 

With  regard  to  cost,  Dr  Clark  reports  that  up  to  the  end 
of  1905  the  Government  had  expended  about  ;^5,ooo  on  anti- 
malaria  measures,  and  estimates  that  i^6,500  would  be  spent 
by  the  end  of  1906 — a  small  amount  to  pay  for  the  good  that 
has  been  done.  The  campaign  in  such  a  thickly  populated 
district  must  be  difficult.  Figures  for  subsequent  years  have 
not  been  obtainable. 

(3).  Cafidta,  Crete. — The  accounts  of  this  excellent  campaign, 
conducted  in  connection  with  the  British  troops  in  Crete,  will 
be  found  in  successive  numbers  of  the  Journal  of  the  Royal 
Anny  Medical  Corps.  The  town  of  Candia,  containing  21,000 
inhabitants,  is  situated  on  the  seashore  of  a  semicircular  plain 
bounded  by  hills.  The  rainfall  is  heavy,  and  the  ground  is 
traversed  by  many  streams,  which  become  torrents  in  winter 
and  nearly  dry  in  summer.  Two  of  them  have  marshy  margins 
near  the  sea.  The  houses  of  the  town  are  of  the  Oriental  type 
and  contain  many  wells.  The  troops  are  accommodated  in 
quarters  to  the  west  of  the  town  and  close  to  it,  and  suffered 
considerably  from  malaria.  Apparently  as  early  as  1902 
Lieutenant-Colonel  J.  V.  Salvage,  R.A.M.C.  [1904],  commenced 
to  examine  into  the  distribution  of  Anophelines  and  to  destroy 
the  larvae  by  drainage,  or  by  closing  or  oiling  the  wells,  or 
putting  fish  into  them,  and  expressed  himself  hopefully  regard- 
ing the  result.  In  March  1903  Major  C.  J.  MacDonald  arrived 
in  Crete  and  continued  the  work  [1905].  He  gives  many 
very  interesting  details.  Works  of  a  permanent  nature  were 
attempted,  and  quinine  prophylaxis  and  mosquito-nets  insisted 
upon.     The  first  results  were  as  below : — 


576  NOTES   ON   SOME   OTHER  WORKS  [Sect.  59 


Years . 
Strength     . 
Admissions 
Rate  % 


I90I 

1902 

1903 

564 

460 

410 

,540 

1,084 

227 

273 

236 

55 

The  admissions  include  simple  continued  fever,  together  with 
malaria,  in  order  to  avoid  error  due  to  diagnosis.  Major 
MacDonald  attributes  the  fall  to  the  measures  taken.  In  1905 
Captain  R.  A.  Cunningham,  R.A.M.C,  adds  a  third  article 
[1905],  in  which  he  stated  that  the  fall  in  the  malaria  rate  had 
continued,  and  was  only  30%  in  1904  compared  with  the  55% 
of  1903.  The  mosquitos  were  so  few  that  it  is  almost  un- 
necessary to  use  a  net  at  night.  In  1905  there  were  246 
admissions,  or  a  rate  of  387%.  Many  men  become  infected 
on  guards  and  outposts. 


By  Colonel  C.   H.   MELVILLE 

Royal  Army  Medical  Corps,  Professor  of  Hygiene,  Royal  Army 
Medical  College,  London 

60.  The  Prevention  of  Malaria  in  War. — Part  I.  The  Lessons 
of  History. — The  history  of  malaria  in  war  might  almost  be 
taken  to  be  the  history  of  war  itself,  certainly  the  history  of 
war  in  the  Christian  Era.  Even  in  Europe  up  till  at  least 
the  middle  of  the  nineteenth  century  all  armies  in  the  field 
were  liable  to  attacks  of  this  class  of  disease,  as  witness  the 
French  and  Austrian  armies  in  the  campaign  in  the  north 
of  Italy  in  the  year  1859.  It  is  probably  the  case  that  many 
of  the  so-called  camp  fevers,  and  probably  also  a  consider- 
able proportion  of  the  camp  dysentery,  of  the  wars  of  the 
sixteenth,  seventeenth  and  eighteenth  centuries  were  malarial 
in  origin.  In  our  own  army,  as  the  writings  of  Pringle  and 
Monro  teach  us,  the  various  campaigns  in  the  Low  Countries 
were  marked  by  severe  outbreaks  of  paludal  fevers,  culminating 
in  the  epidemic  that  wrecked  the  ill-fated  Walcheren  expedition 
just  one  hundred  years  ago.  It  would  be  out  of  place  here  to  do 
more  than  mention  these  earlier  histories,  but  the  Walcheren 
disaster  merits  more  than  passing  notice,  for  several  reasons. 
In  the  first  place,  it  occurred  in  comparatively  recent  years. 
There  must  be  men  still  alive  who  can  remember  having  seen 
and  spoken  to  survivors  of  the  expedition,  some,  at  least,  of 
whom  must  have  carried  the  marks  of  their  sufferings  to  the 
grave.     In  the  next,  the  close  proximity  of  the  scene  of  action 

577  20 


578  THE   PREVENTION   OF   MALARIA   IN   WAR        [Sect. 

to  our  own  shores  struck  even  contemporaries  with  a  sense 
of  the  reaHty  of  the  disaster.  These  two  characteristics  tend 
to  make  this  outbreak  one  of  peculiar  interest ;  but  there  are 
others  of  even  greater  value  than  interest,  which  bear  very 
closely  on  the  question  of  prevention  of  malarial  fevers  in 
campaigns  of  the  present  day.  Of  these  the  first  is  that  the 
locality  selected  for  the  debarkation  of  the  troops  was  one 
notoriously  unhealthy  on  account  of  malarial  fevers.  Already, 
in  1747,  the  force  landing  in  Zealand  had  suffered  to  such  an 
extent  from  this  cause  that,  according  to  Sir  John  Pringle,  some 
of  the  battalions  in  South  Beveland  and  Walcheren  had  but 
100  men  fit  for  duty,  being  less  than  one-seventh  part  of  their 
whole  number.  Another  experience  repeated  in  the  expedition 
of  1809  was  that  the  men-of-war  which  lay  at  anchor  in  the 
channel  between  South  Beveland  and  Walcheren,  even  during 
the  worst  period  of  the  distemper,  were  not  affected  with  either 
flux  or  fever,  but  enjoyed  the  most  perfect  health.  In  the  light  of 
our  present-day  knowledge  this  coincidence  is  easy  of  interpreta- 
tion ;  but  the  practical  lesson  to  be  drawn  was  clear,  or  should 
have  been  clear,  even  in  1809,  namely,  that  on  a  malarial  coast 
troops  should  not  be  landed  from  the  transports  until  all  steps 
are  ready  for  an  immediate  advance.  It  was  the  preliminary 
delay  under  the  walls  of  Flushing  that  laid  the  army  of  Lord 
Chatham  open  to  the  first  onslaughts  of  disease.  An  early 
advance  into  the  comparatively  higher  ground  of  the  interior 
would  undoubtedly  have  done  much  to  check  the  disease.  In 
the  second  place,  the  season  of  the  year  selected  for  the  expedi- 
tion was  notoriously  the  most  unhealthy  of  the  year.  And  this 
fact  also  was  on  record.  Sir  John  Pringle  wrote  as  follows  in 
the  year  1765  :  "The  epidemics  of  this  country  may  therefore 
be  generally  dated  from  the  end  of  July,  or  the  beginning  of 
August,  under  the  canicular  heats  :  their  sensible  decline,  about 
the  first  falling  of  the  leaf;  and  their  end,  when  the  frosts  begin." 
Here,  again,  the  lesson  was  as  plain  as  the  warning.  If  a  force 
has  to  land  in  a  malarious  locality,  then  the  unhealthy  season 


6o]  WALC  KEREN,    1809  579 

should  be  carefully  avoided.  How  long  it  took  before  that 
lesson  was  learnt  the  records  of  our  earliest  campaign  in 
Ashanti,  and  the  experiences  of  the  French  in  Madagascar, 
show  only  too  clearly.  And  lastly,  there  was  no  selection  of 
the  men.  Davis,  who  was  appointed  to  attend  the  troops  on 
their  return  to  England,  in  his  "  Scientific  and  Popular  View  of 
the  Fever  of  Walcheren  "  (p.  vii.),  alludes  to  the  fact  that  the 
troops  consisted  of  "  numbers  of  young  men  unaccustomed  to 
fatigue  and  the  hardships  of  a  military  campaign."  It  may  be 
accepted  as  one  of  the  most  important  points  in  the  conduct 
of  a  campaign  in  a  malarial  locality  that  the  men  should  be 
seasoned  soldiers,  free  from  the  taint  of  previous  severe  malarial 
infection,  but  accustomed  by  experience  to  the  proper  camp 
discipline  essential  to  the  prevention  of  paludal  diseases. 

The  expedition  left  the  shores  of  England  on  the  28th  July 
1809,  and  disembarked  in  Middleburg  and  Walcheren  on  the 
29th  and  30th  of  the  same  month.  The  siege  of  Flushing  was 
at  once  undertaken,  and  this  place  surrendered  on  the  15th.  Up 
till  that  date,  with  the  exception  of  the  men  killed  in  action, 
there  had  been  no  deaths  in  the  force  of  17,000  men,  and 
though  the  medical  authorities  on  the  spot  were  justifiably 
anxious,  in  view  of  the  medical  history  of  the  locality,  the 
general  public  were  far  from  sharing  in  this  apprehension, 
"  observing  that  the  notion  of  the  unhealthiness  of  Walcheren 
being  so  great  that  it  ought  not  to  be  garrisoned  by  British 
troops,  was  too  absurd  to  deserve  much  notice  ;  as  it  might 
probably  be  as  unhealthy  as  Romney  marsh,  or  the  hundreds 
of  Essex."  ^  This  was  on  the  23rd  August,  but  "  a  different 
impression  was  felt  in  Walcheren,  for  as  early  as  the  25th  it 
appears,  by  a  letter  from  the  expedition,  that  the  interruption 
to  active  operations  which  had  then  taken  place  from  the 
rapidity  with  which  the  disease  was  spreading  had  caused  much 
regret."  -  By  the  29th  August  there  were  3,000  men  in  hospital 
out  of  a  total  of  about  25,000  men.     Early  in  September  there 

1  Davis,  p.  xi.  ^  Ibid.  p.  xi. 


58o  THE    PREVENTION    OF    MALARIA   IN   WAR        [Sect. 

were  upwards  of  7,000  men  in  the  different  hospitals,  and  by 
the  14th  it  was  estimated  that  out  of  a  strength  of  15,000  in 
Walcheren,  10,000  were  actually  sick,  the  deaths  then  averaging 
at  from  25  to  30  per  day.  The  repatriation  of  the  troops  to 
England  had  already  begun,  and  "about  the  13th  they  began 
to  arrive  at  Deal,  where  soon  after  the  mortality  in  one  hospital 
amounted  to  14  in  one  day  .  .  .  indeed  the  mortality  among 
those  who  first  arrived  in  England  was  greater,  comparatively, 
than  at  the  same  period  even  in  Flushing,  for  there  the  whole 
daily  mortality,  though  seldom  less  than  50,  for  some  time 
previous  to  the  12th  had  never  on  any  one  day  exceeded  100."^ 
At  the  latter  place,  "  on  the  23rd  of  September,  the  sick  report 
included  218  officers,  382  sergeants,  190  drummers  and  9,046 
privates."^  From  that  date  the  fever  subsided.  On  the  26th 
there  were  9,798  in  hospital,  and  on  the  30th  8,600,  and  though 
the  army  was  disabled  and  vanquished,  its  invisible  enemy 
gradually  slackened  its  pursuit,  and  the  "  remnant  of  an  army  " 
returned  to  England  on  the  23rd  December,  having  faced  fifteen 
days'  fighting  with  247  casualties,  and  two  months'  fever  with 
more  than  4,000  dead.  And  how  about  the  wounded  in  this 
appalling  struggle.?  Years  afterwards  the  men  who  survived 
still  showed  in  shattered  constitutions  the  results  of  the  in- 
eptitude which  planned,  and  the  inefficiency  which  led  the 
expedition  of  1809. 

The  expedition  to  Walcheren  is  one  of  the  most  striking 
instances  of  the  part  that  epidemiology  should  play  in  strategy. 
There  were,  on  political  and  military  grounds  if  on  no  other, 
doubts  as  to  the  advisability  of  attacking  the  French  in 
the  Low  Countries.  The  known  unhealthiness  of  Zealand 
should  have  been  recognised,  and  should  have  acted  as  the 
decisive  factor.  In  whatever  part  of  the  French  dominions  a 
British  force  had  been  landed  at  that  season  of  the  year,  the 
neighbourhood  of  Walcheren  was  the  last  that  should  have 
been  selected. 

^  Davis,  p.  xvii.  *  Ibid.  p.  xviii. 


6o]  ASHANTI,    1864  581 

In  no  other  campaign  during  the  "  Great  War  "  did  malarial 
fevers  play  so  commanding  a  role  as  in  the  expedition  of  1809, 
though  it  is  true  that  both  in  Estremadura  and  before  Cuidad 
Rodrigo,  the  army  under  Sir  Arthur  Wellesley  suffered  notably 
from  this  type  of  disease.  The  chiefinterest,  however,  of  paludism 
attaches  historically  in  the  nineteenth  century  to  campaigns 
in  the  tropics,  and  as  this  will  undoubtedly  be  even  more  the 
case  in  years  to  come,  I  do  not  propose  to  refer  in  this  brief 
sketch  to  any  other  class  of  enterprise.  And  I  will  further 
limit  myself  to  a  consideration  of  two  of  our  own  expeditions 
to  Ashanti,  and  to  that  of  the  French  to  Madagascar  in  1895, 
since  these  present  typical  instances  of  small  wars  where  success 
or  failure  depended  not  on  the  bravery  of  the  men,  or  the 
tactical  skill  of  their  leaders,  but  entirely  on  the  amount  of 
forethought  paid  to  the  problems  of  disease  at  home,  and  to 
the  translation  of  that  forethought  into  terms  of  energetic  action 
on  the  spot. 

Passing  over  the  earlier  unsuccessful,  or  only  partially 
successful  campaigns  of  1822,  1824  and  1833  in  Ashanti,  I 
shall  begin  with  that  of  1864.  Of  this  expedition  the  late 
Surgeon-General  Gore  (sanitary  officer  with  the  expedition  of 
1873)  writes  ("  Medical  History  of  our  West  African  Campaigns," 
p.  10) :  "  It  can  scarcely  be  called  a  war,  as  an  enemy  was 
never  seen,  or  a  grain  of  powder  expended  ;  our  troops  were 
defeated  by  disease,  much  of  which  was  preventable."  He  goes 
on:  "In  August  of  the  former  year  (1863),  the  right  wing  of 
the  4th  West  India  Regiment  landed  at  Cape  Coast  Castle. 
Preparations  were  at  once  commenced  for  the  future  advance. 
Stores  were  collected  and  paths  cut,  these  operations  lasting 
until  December,  during  the  continuance  of  which  the  men 
suffered  much  from  dysentery,  remittent  and  intermittent  fever." 
This  point  is  worth  noting.  One  of  the  most  essential  pre- 
cautions in  the  case  of  tropical  campaigns  is  to  see  that  the 
collection  of  stores  is  carried  out  in  anticipation  of  the  landing 
of  the  expeditionary  force.     The  campaign,  as  already  stated, 


582  THE   PREVENTION   OF   MALARIA   IN   WAR        [Sect. 

was  a  fiasco.  By  the  end  of  March  one  quarter  of  the  strength 
was  in  hospital,  and  by  the  middle  of  May  all  the  members 
of  the  original  force  at  Prahsue  were  relieved.  The  admissions 
in  1864  amounted  to  over  1,600,  and  the  deaths  to  a  fraction 
under  60  per  1,000.  It  must  be  noted,  too,  that  these  troops  were 
not  Europeans,  but  black  troops  from  the  West  India  regiments. 
Of  60  European  officers  35%  succumbed  to  the  effect  of  disease. 
The  lessons  of  this  campaign  were  not,  however,  lost. 

Early   in    1873  the  Ashantis  made  one  of  their  periodical 
inroads  into  the  Gold  Coast  Protectorate.     Owing  to  the  scanty 
numbers  and  scattered  distribution  of  the  British  garrison,  our 
men  were  confined  to  the  defence  of  the  posts  held  by  them. 
A  small  reinforcement  of  Marines  was  despatched  from  England, 
and  reached  Elmina,   the  most  seriously  -  threatened  post,  by 
the  1 2th  June,  inflicting  on  the  next  day  a  serious  repulse  on 
the  enemy.     Affairs  remained  in  statu  quo,  the  enemy  becoming 
somewhat    less    active,   but    still    maintaining    a    threatening 
attitude,   until,   in    September,  an  attack  on  the  boats  of  the 
Rattlesnake  demonstrated  that  sterner  measures  must  be  taken 
to  deal  finally  with  them.     Sir  Garnet  Wolseley  arrived  from 
England  on  the  2nd  October,  and  at  once  began  the  erection 
of  wooden  huts,  and  the  enlistment  of  native  artificers,  labourers 
and    porters,   as   well   as    the   enrolment    of    local   levies   and 
regiments    under   specially  -  selected    officers,   "  it   having   been 
thought  that  with  European  organisation  and  guidance  Ashanti 
armies  might  well  be  successfully  encountered  by  Africans  of 
other  races."  ^     The  first  blow  was  struck  on  the  14th  October, 
when  a  force  advanced  from  Elmina  and  captured  and  burnt 
the   village   of  Essaman,    with   but  trifling  loss.     As   a  result 
of  this   blow   the  Ashantis  prepared  to  retreat  to  their  own 
country,  but  Sir  Garnet  decided  that  to  complete  their  punish- 
ment a  force  containing  a  strong  European  contingent  should 
be   sent    into    Ashanti    territory.      In    spite    of    well-founded 
apprehension   as  to  the  consequences  of  employing  European 

1  A.M.D.  Report,  1873,  p.  232. 


6o]  ASHANTI,    1873  583 

troops  in  the  climate  of  the  West  Coast,  it  was  decided  that 
a  force  corresponding  to  the  requirements  formulated  by 
General  Wolseley  should  be  despatched,  it  being  considered, 
as  a  result  of  the  experience  of  campaigns  in  low-lying,  swampy 
districts  of  other  tropical  countries,  that  "  there  was  a  season 
of  comparative  healthiness  corresponding  to  the  driest  season 
of  the  year,  and  that  in  this,  with  suitable  precautions  and 
limitations,  Europeans  might  undertake  field  service  in  the 
Gold  Coast  country."^ 

Pending  the  arrival  of  the  European  force  operations  were 
undertaken  with  the  troops  at  hand  with  a  view  to  clearing 
the  enemy  from  the  territory  of  the  Protectorate,  and  facilitating 
the  advance  of  the  punitive  force  as  far  as  the  banks  of  the 
Prah.  Sites  were  selected  between  the  base  at  Cape  Coast 
and  the  river  named,  for  the  formation  of  camps,  temporary 
barracks  being  erected  at  these  places.  In  all,  eight  such  sites 
were  fixed,  the  average  distance  between  one  camp  and  the 
next  being  a  fraction  over  nine  miles.  The  object  in  view 
was  to  ensure  that  "  the  troops  were  to  march  into  stationary 
camps,  and  to  reach  the  Prah — the  second  base  of  the  expedition 
— as  little  fatigued  as  possible,  so  that  the  force  might  start 
thence  with  the  men  in  the  highest  state  of  efficiency,  and  strike 
the  intended  blow  before  it  was  materially  reduced  by  sickness."  ^ 
Eventually,  the  first  detachment  of  European  troops  landed 
on  the  I  St  January  1874,  and  the  whole  strength  was  assembled 
and  the  river  crossed  on  the  21st.  Some  rather  smart  fighting 
occurred  at  Amoaful  on  the  31st  January,  and  again  outside 
Coomassie  on  the  4th  February.  The  city  was  entered  that 
same  evening,  and  burnt  and  evacuated  on  the  6th.  The  entire 
force,  with  the  exception  of  some  of  the  irregular  corps,  recrossed 
the  Prah  by  the  14th  February,  that  is,  within  three  weeks  of 
the  date  of  first  crossing  it.  The  42nd  Highlanders,  which 
was  the  first  regiment  to  land,  was  also  the  last  to  leave.  The 
period  that  elapsed  between  landing  and  embarkation  was  eight 
^  A.M.D.  Report,  1873,  p.  236,  2  jUfi^  p_  246, 


584  THE   PREVENTION   OF   MALARIA   IN  WAR        [Sect. 

weeks  all  but  one  day.  The  admission  rate  was  58  per  1,000 
for  European  rank  and  file,  and  the  death-rate  i8"2  per  1,000, 
Five  British  officers  and  13  men  were  killed  in  action,  while 
21  and  40  of  these  two  classes  respectively  died  of  disease. 
This  striking  contrast  between  the  two  campaigns  of  1864 
and  1874  deserves  to  be  noted.  The  keynotes  of  success  in 
the  latter  case  were  careful  preliminary  preparation,  and  swift 
and  rapid  execution.  Failure  in  the  former  expedition  was 
due  to  "  unselected  men,  under  officers  many  of  whom  had 
already  suffered  from  illness,  not  especially  well  equipped  or 
cared  for,  remaining  in  the  field  at  a  bad  season,  and  languishing 
in  inaction  month  after  month."  ^ 

The  only  other  historical  instance  on  which  I  shall  dwell 
is  the  French  campaign  in  Madagascar  in  1895.  The  necessity 
for  an  expedition  to  Madagascar  was  recognised  in  the  late 
months  of  1894,  but  already  for  a  year  prior  to  the  actual 
parliamentary  sanction  for  the  despatch  of  a  force,  the  Naval 
and  War  Departments  had  had  such  a  possibility  under  con- 
sideration, and  the  former  had,  with  commendable  forethought, 
caused  reconnaissances  to  be  made  of  the  possible  points  of 
disembarkation,  and  of  the  best  lines  of  advance.  In  August 
1894  an  inter-Departmental  Committee  was  formed  at  the 
Foreign  Office,  in  which  the  two  departments  already  named 
and  the  Colonial  Office  collaborated  in  the  production  of  a 
joint  report  on  the  geographical  and  military  situation,  with 
suggestions  as  to  the  composition  of  the  expeditionary  force, 
and  the  various  measures  to  be  adopted  to  meet  the  grave 
difficulties  presented.  There  was  in  fact  no  want  of  pre- 
paratory consultation.  About  the  middle  of  November  it  was 
decided  to  entrust  the  execution  of  the  plans  to  the  Ministry 
of  War,  and  accordingly  a  fresh  commission  was  formed,  of  an 
advisory  nature,  which  sat  at  the  War  Office  under  the  direction 
of  the  Chief  of  the  General  Staff,  and  was  presided  over  by 
General  Duchesne,  specially  selected  for  the  chief  command  of 

1  A.M.D.  Report,  1837,  p.  237. 


6o]  MADAGASCAR,    1895  5^5 

the  expeditionary  force.  On  this  commission  all  departments 
concerned  were  represented,  and  a  second  commission  entrusted 
with  a  fuller  consideration  of  details  was  also  appointed. 

Meanwhile  time  passed.  It  was  necessary  to  start  active 
operations  by  May  at  the  latest,  and  in  fact  the  advance  guard 
of  the  expedition  landed  at  Majunga  twenty-four  days  before 
the  last-named  commission  completed  its  work.  Even  so  the 
War  Office  was  by  no  means  independent  in  its  management 
of  affairs.  Diplomatic  arrangements  still  remained  under  the 
Foreign  Office,  while  the  troops  available  came  partly  under 
the  Ministry  of  Marine,  partly  under  the  Colonial  Depart- 
ment, and  partly  under  the  War  Office.  As  one  result  of 
the  complication  of  authority  and  responsibility  the  force  was 
compelled  to  march  for  forty-three  days  through  a  malaria- 
infested  country,  instead  of  proceeding  by  steamer,  though  the 
necessity  for  the  latter  expedient  had  been  recognised,  and 
arrangements  to  that  end  begun.  Transport  being  deficient 
and  unsuitable,  the  troops  were  forced  to  advance  in  heavy 
marching  order,  in  spite  of  the  heat.  Medical  equipment  was 
left  behind,  and  even  quinine  was  often  not  to  be  had.  No 
special  hutments  were  provided,  and  Malagasy  huts  had  to 
be  utilised  even  at  the  very  base.i  "  From  the  ist  to  the  24th 
March  the  troops  were  almost  entirely  occupied  in  disembark- 
ing '>nateriel,  in  building  shelters  and  making  roads,  work  made 
all  the  more  laborious  by  the  lack  of  native  labour,  and  the 
heavy  rain."  Just  as  there  was  no  lack  of  forethought  at  home, 
so  there  was  no  lack  of  energy  at  the  front.  Unfortunately, 
the  divorce  between  the  two  was  complete. 

Eventually  the  supply  of  water  at  Majunga  ran  short,  the 
apparatus  for  distillation  being  insufficient,  and  an  advance 
had  perforce  to  be  made.  One  company  of  engineers  that  left 
Majunga  225  strong,  arrived  at  Suberbieville  with  only  25 
worn-out  men  still  effective.  It  is  unnecessary  to  prolong  this 
narrative.      Reynaud    gives    in    his   excellent  "  Considerations 

1  Reynaud,  p.  312. 


586  THE    PREVENTION    OF    MALARIA   IN   WAR        [Sect. 

Sanitaires  sur  I'Expedition  de  Madagascar,"  a  detailed  account 
of  the  misfortunes  that  continued  to  befall  the  expedition. 
From  Suberbieville  a  flying  column  was  despatched  to  Antan- 
anarivo, which  it  reached  on  the  30th  September  after  incredible 
exertions,  leaving  ten  per  cent,  of  its  strength  on  the  road. 
The  French  soldiers  christened  this  column  "  la  colonne  Marche- 
ou-Creve,"  a  not  inappropriate  expression  for  a  force  where  to 
fall  out  meant  mutilation  and  death  at  the  hands  of  a  cowardly 
enemy.  And  yet  many  fell  out  and  remained  to  die  of  starva- 
tion, worn  out  with  suffering  and  illness.  And  as  Dr  Reynaud 
reminds  us,  this  was  the  march  of  a  conquering  army,  not  a 
precipitate  flight  before  a  victorious  enemy,  but  the  culminating 
point  of  an  expedition,  the  details  of  which  had  been  carefully 
thought  out.  The  last  remnants  of  this  unfortunate  army  left 
the  shores  of  Madagascar  on  the  28th  December,  leaving  behind 
them  4,498  dead  out  of  the  combatant  force  alone.  Amongst 
the  auxiliaries  it  was  estimated  that  there  were  3,000  deaths, 
whilst  as  regards  non-combatants  the  numbers  are  beyond 
calculation.  The  proportion  of  deaths  amongst  the  combatants 
was  equivalent  to  320  per  1,000  of  strength,  due  almost  entirely 
to  malarial  fevers  and  their  sequelae.  The  deaths  in  action 
were  13,  and  in  addition  there  were  88  men  wounded.  The 
causes  of  this  disaster  were  the  antitheses  of  those  which  led  to 
our  success  in  Ashanti  in  1874  —  confused  councils,  divided 
authority,  and  delayed  execution. 

Part  II.  Practical  Measures. — We  now  come  to  the  im- 
portant question  of  the  prevention  of  malarial  diseases  in  war. 
I  propose  to  discuss  this  subject  under  two  heads.  First,  the 
measures  to  be  adopted  in  anticipation  of  the  opening  of 
hostilities,  and  secondly,  those  to  be  carried  out  during  the 
actual  progress  of  active  operations. 

Measures  to  be  adopted  in  anticipation  of  the  outbreak  of 
hostilities. — Before  actually  detailing  these,  it  is  necessary  to 
insist  on  their  enormous  importance,     It  is  not  going  too  far 


6o]  PRACTICAL    MEASURES  587 

to   say   that    the   success   of  any   tropical   campaign    depends 
infinitely   more   on   the  administrative   measures  taken  in  the 
preparation  for  the  expedition  than  on  the  courage  and  fighting 
capacity  of  the  troops  engaged.     The  success  of  the  Ashanti 
campaign  of   1874  was   ensured  in  Pall   Mall  before  ever  Sir 
Garnet   Wolseley   left    England,  and    the   fate   of  the   French 
expedition  to   Madagascar  in    1895  was  decided  in  Paris  and 
not  at   Majunga  or   Suberbieville.     The  only  serious  problem 
in  a  tropical  campaign  is  disease.     This  has  been  proved  time 
and  again.     No  soldier  will  for  a  moment  pretend  that  either 
in  Burma  or  Ashanti  the  fighting  was  of  a  serious  nature,  and 
the   same  is  true  of  the    French   army  in  Madagascar.     The 
only  obstacle  to  be  feared  was  disease,  and  most  importantly 
malaria.     Now  there  is  this  difference  between  a  human  enemy 
and   disease.      The   former   may    alter   his    plans   at   the   last 
moment,  and  our  plans  may  have  to  be  changed  accordingly. 
But  disease  does  not  alter  its  laws.     As  far  as  we  know  or 
can  guess  at  those  laws  we  are  able  to  calculate   confidently 
on   their   regularity,  and    our   plans  can  be  fixed  accordingly. 
It  is  almost  a  platitude  to  say  that  the  success  of  any  tropical 
campaign    is   settled   as    much    in   Whitehall  as  on  the  actual 
spot.     An  ill-provided,  ill-thought-out  expedition  can  only  end 
in  disaster,  however  brave  the  soldier,  and  however  skilled  his 
commander.     On  the  other  hand,  but  little  military  skill  and 
no  extraordinary  amount  of  courage  is  necessary  to  enable  a 
small  picked  force  of  healthy  Europeans,  armed  with  modern 
weapons,  to  march  through  the  territory  of  the  most  powerful 
savage   tribe   in   the   tropics.      But   what  is   necessary   is  that 
the  objective  should  be  clear,  the  means  exactly  proportioned 
to  the  end,  and  all  things  necessary  provided  before  the  start 
is  made.     It  was  an  observance  of  these  principles  that  made 
the  Ashanti  campaign  of  1874  a  brilliant  success,  and  neglect 
of  them  that  turned  the  French  expedition  to  Madagascar  in 
1895  into  a  dismal  failure. 

The   composition   and   strength   of   the    force    sent    is    an 


588  THE   PREVENTION   OF   MALARIA   IN   WAR        [Sect. 

important  consideration.  One  of  the  greatest  initial  mistakes 
made  by  the  French  Government  in  1895  was  sending  too 
large  a  force,  and  one  in  which  the  proportion  of  Europeans 
was  unduly  great.  As  already  stated,  the  military  foe  is  the 
one  least  to  be  feared  in  a  tropical  campaign.  Locally  raised 
troops  drilled  and  officered  by  Europeans  should  be  capable 
of  meeting  their  own  tribesmen,  undrilled,  unofficered  and 
poorly  armed.  A  stiffening  of  Europeans  is  necessary,  but  no 
more.^  General  Gallieni,  in  his  "  Deux  Campagnes  au  Soudan 
Francais,"  lays  down  this  principle  very  clearly.  "  Taking  into 
account,"  he  says,  "  the  unhealthiness  of  the  climate  and  the 
peculiarly  trying  conditions  that  characterise  our  campaigns 
in  the  Soudan,  I  did  not  wish  to  encumber  myself  with  too 
large  a  force  of  Europeans.  I  contented  myself  with  a  strong 
company  of  Marine  infantry.  In  action  this  body  would  be 
available  as  a  reserve  to  the  native  troops.  The  right  class 
of  soldier  for  the  Soudan  is  the  Senegalese  rifleman."  The 
following  are  the  numbers  respectively  of  Europeans  and 
natives  employed  in  some  of  our  campaigns : — 

Abyssinia:  3,655  Europeans,  9,833  natives, 

Ashanti  (first  expedition,  1 868),  2,284  Europeans,  2,377  black 
troops. 

Ashanti  (second  expedition,  1874),  1,050  Europeans,  2,050 
black  troops. 

It  will  be  noted  that  the  disastrous  expedition  to  Ashanti 
in  1868  was  the  only  one  in  which  there  was  an  equality  in 
numbers  between  the  two  classes.  In  Madagascar  in  1895 
the  French  had  11,000  European  soldiers  to  3,800  natives  (two 
battalions  Algerians,  one  battalion  Malagasys,  and  one  battalion 
Haussas).  It  may  be  definitely  laid  down  that  those  branches 
of  the  service  not  immediately  concerned  in  fighting  should 
be  composed  entirely  of  natives,  sufficient  Europeans  only 
being  sent  to  superintend  their  work.  This  rule  applies  to 
the  Engineers,  the  Supply  and  Transport  Departments,  and  to 

^   Reynaud,  p.  247. 


6o]  SELECTION   OF   MEN  589 

a  great  extent  to  the  Medical  Department.  Men  actually 
engaged  in  nursing  the  sick  should  be  European,  but  cooks 
(with  a  few  picked  exceptions)  and  the  general  duty  section 
generally  should  be  replaced  by  natives.  The  composition  of 
the  force  should  be  such  that  no  fatigues  and  no  unnecessary 
non-combatant  duties  should  be  imposed  on  Europeans. 

The  next  point  to  be  thought  of  is  the  selection  of  the 
men  to  form  the  force.  These  should  be  carefully  picked. 
All  men  with  a  previous  history  of  severe  or  repeated  malaria 
should  be  excluded.  As  regards  rank  and  file  this  rule  should 
be  absolute.  No  man  whose  blood  contains,  or  probably  con- 
tains, the  malarial  plasmodium  should  be  allowed  to  proceed 
on  the  expedition,  partly  in  his  own  interests,  but  mainly 
in  those  of  his  comrades.  As  regards  officers,  and  more 
particularly  those  who  possess  special  qualifications  for  em- 
ployment, some  latitude  must  be  given.  In  such  cases  three 
or  four  examinations  of  the  blood  should  be  made,  and  if 
Plasmodia  are  not  found,  a  previous  malarial  history  need 
not  exclude.  If  plasmodia  are  present,  the  value  of  the 
individual  as  a  strategical  or  tactical  factor  must  be  balanced 
against  his  potential  danger  as  a  disease  centre.  With  an 
educated  man  occupying  a  tent  by  himself  the  danger  is 
obviously  not  so  great  as  in  the  case  of  a  comparatively 
uneducated  private  soldier  sleeping  amongst  his  comrades. 
No  young  soldiers  should  be  sent.  Not  because  there  is,  as 
far  as  we  know,  any  special  predisposition  connected  with 
immaturity,  but  because  the  less  tough  a  man  is,  the  less  able 
he  is  to  withstand  the  hardships  and  privations  inseparable 
from  tropical  active  service,  and,  therefore,  the  more  likely  he  is 
to  break  down,  and  consequently  lower  his  powers  of  resistance. 
It  must  be  remembered  that  in  a  malarious  country  a  man 
with  Plasmodia  in  his  blood  is  just  as  much  a  focus  of  infection 
as  a  small-pox  patient  would  be  in  a  barrack-room  at  home. 
Any  man,  therefore,  who  is  likely  to  break  down  is  a  danger 
to  his  comrades,  and  should   be  rejected.     The  made  soldier 


590  THE   PREVENTION   OF   MALARIA   IN   WAR        [Sect. 

has  the  further  advantage  that  he  is  more  knowledgeable  as 
regards  the  thousand  details  that  make  the  difference  between 
comfort  and  discomfort,  which  in  the  tropics  is  almost  equiva- 
lent to  saying  health  and  disease,  than  the  raw  youngster.  He 
knows  better  how  to  cook,  how  to  rig  up  rough  shelters,  what  to 
eat,  drink  and  avoid,  and,  generally,  how  to  look  after  himself. 
Syphilis,  of  course,  should  exclude,  unless  the  man  has  special 
qualifications.  Some  German  authorities  advise  that  all  men 
should  be  tested  prior  to  embarkation,  to  see  whether  or  no 
they  possess  any  special  intolerance  to  quinine — a  somewhat 
meticulous  precaution.  An  absolute  intolerance  of  this  drug 
is  rare,  as  a  matter  of  experience. 

The  next  point  to  be  considered  is  the  selection  of  the 
theatre  of  war,  and  more  especially  the  selection  of  the  line 
of  advance  into  the  enemy's  country,  and  the  base  of  operations. 
As  regards  the  first  named,  naturally  not  much  can  be  done 
by  the  sanitarian.  If  the  enemy  inhabits  a  malarial  country, 
or  the  key  of  the  strategical  situation  lies  in  a  district  where 
these  diseases  are  rife,  the  fact  has  to  be  faced,  and  made  the 
best  of  when  the  time  comes.  Still  the  Walcheren  expedi- 
tion is  a  notable  instance  where  the  epidemiological  factor 
should  have  been  given  decisive  weight.  As  regards  the  line  of 
advance  and  the  base  of  operations  the  case  is  different.  One 
of  the  most  important  duties  devolving  on  the  Intelligence 
Department,  in  connection  more  particularly  with  campaigns 
in  the  tropics,  is  the  collection  of  information  as  regards  the 
health  conditions  of  the  country  to  be  invaded.  If  a  preliminary 
reconnaissance  is  feasible,  a  specially-selected  medical  officer 
should  be  entrusted  with  this  duty.  He  should,  if  possible, 
be  acquainted  with  the  country  already,  but  most  certainly 
he  should  have  a  thorough  practical  knowledge  of  malarial 
prevention  and  of  tropical  entomology.  He  should  ascertain 
the  spots  most  suitable  for  landing  troops,  and  note  the  possi- 
bilities in  the  way  of  systematic  malarial  prevention  possessed 
by  each.     He  should,  at  the  same  time,  draw  up  schemes  for 


6o]  SELECTION    OF    SEASON  59i 

such  work,  giving  an  estimate  of  time  necessary  for  its  com- 
pletion, number  of  labourers  required,  and  so  on.  His  recon- 
naissance should  be  pushed  as  far  up  the  line  of  projected 
advance  as  possible,  and  he  should  select  sites  for  camps  and 
posts,  temporary  and  permanent.  It  must  be  kept  in  mind 
that  dealing,  as  we  mostly  are  in  these  cases,  with  a  savage 
foe,  the  first  energies  of  the  force  should  be  directed,  not  against 
the  human  enemy,  but  against  the  far  more  intractable  and 
deadly  insect  foe.  Superiority  in  armament  should  be  more 
than  sufficient  to  cancel  the  tactical  defects,  if  any,  of  a  position 
selected  primarily  on  sanitary  grounds.  More  especially  would 
this  be  the  case  if  the  base  were  situated  (as  in  the  majority 
of  cases  it  will  be)  on  a  coast  where  the  fire  from  the  fleet 
can  be  made  available  to  assist  the  force  on  land.  It  would 
be  a  mistake,  however,  to  suppose  that  there  need  necessarily 
be  any  conflict  between  the  sanitary  authorities  and  the  staff 
of  the  expedition.  A  good  military  site  is  in  most  cases 
elevated,  and  free  from  immediate  obstruction  to  the  view. 
The  post,  therefore,  will  be  more  or  less  elevated,  and 
the  surrounding  jungle  must  be  burnt  or  cut  down,  both 
important  points  as  regards  the  prevention  of  malaria. 
Proximity  to  drinking-water  must  not  be  allowed  to  overrule 
the  importance  of  avoiding  as  far  as  possible  all  mosquito- 
breeding  grounds. 

The  place  being  fixed,  the  next  point  in  order  of  importance 
is  time.  Here  greater  latitude  is  allowable,  and  it  must  be  at 
once  stated  emphatically  that  only  the  most  urgent  political 
necessity,  the  rescue,  for  instance,  of  a  beleaguered  garrison, 
can  justify  the  despatch  of  a  European  force  to  a  malarious 
country  at  the  unhealthy  season  of  the  year.  As  an  instance 
of  this  may  be  noted  the  Ashanti  war  of  1873.  The  first 
inroad  of  the  Ashantis  took  place  in  May  of  that  year, 
but  though  the  various  threatened  posts  were  reinforced  as 
necessary,  the  first  actual  blow  was  not  struck  by  Sir  Garnet 
Wolseley  till  the   14th  October.      The  Ashanti  expedition  of 


592  THE   PREVENTION   OF   MALARIA   IN   WAR        [Sect. 

1864  shows  equally  well  the  results  of  neglecting  this  obvious 
precaution.  It  is  necessary  to  insist  on  this  point.  The 
expedition  in  1864  was  undertaken  in  the  unhealthy  season — 
March  to  June — and  the  mortality  and  sickness,  almost  entirely 
from  malaria,  were  so  great  that  the  entire  enterprise  collapsed. 
Malaria  was  just  as  rife  on  the  coast  in  1873  as  in  1864;  the 
mortality  among  the  Marines  in  the  interval  between  May  and 
October  of  the  former  year,  whilst  Wolseley  was  waiting  for 
the  auspicious  moment  to  strike  his  blow,  was  I7'30  per  100, 
greater,  as  Sir  Anthony  Home  (A.M.D.  Report,  1873,  p.  225) 
points  out,  than  that  of  the  army  in  Walcheren  :  whilst  that 
of  the  expeditionary  men  after  October  was  only  3"  14%-  It 
must  be  remembered  that  scientific  prevention  of  malaria,  as 
we  now  understand  the  term,  was  as  little  known  in  1873  ^^  it 
had  been  nine  years  earlier.  The  striking  difference  in  the 
incidence  of  disease  in  the  two  expeditions  was  due,  in  great 
part,  to  the  careful  selection  of  the  season  in  which  active 
operations  were  carried  out. 

The  question  of  housing  of  troops  is  most  important.  For 
this  purpose  portable  mosquito-proof  houses  should  be  provided. 
These  can  be  constructed  of  any  material,  but  probably  some 
of  the  modern  fire-proof  compositions  (Eternit,  etc.)  would  be 
found  the  most  convenient.  These  should  be  provided  in 
sufficient  numbers  to  house  all  European  details  left  at  the 
base  throughout  the  progress  of  active  operations,  with  a 
margin  of  10  to  20%.  This  is  essential.  No  European  should 
be  made  to  sleep  exposed  to  the  attacks  of  mosquitos  for  a 
single  night,  where  this  risk  can  by  any  possible  means  be 
avoided.  If  the  force  is  kept,  as  regards  Europeans,  within 
reasonable  limits,  there  should  be  no  difficulty  in  this  respect. 
Any  barracks  of  this  nature  sent  out  should  be  shipped  on  the 
transports  carrying  the  troops,  and  it  ought  to  be  laid  down 
that  no  men  should  be  landed  in  advance  of  their  barracks. 
If  the  line  of  advance  is  easy  and  well  known,  and  if  transport 
is  easily  procurable,  then  huts  for  Europeans  should  be  sent 


6o]  RATIONS,    CLOTHING,    NETS,   FANS  593 

forward  to  the  first  camps  on  the  Lines  of  Communication, 
especially  those  likely  to  be  occupied  permanently,  as  in 
Ashanti  in  1873- 1874.  If  the  correct  view  of  the  class  of 
campaign  be  clearly  recognised,  which  is,  that  the  contest  is 
one  not  so  much  with  man  as  with  disease,  and  that  the 
defensive  measures  necessary  should  be  directed  not  against 
the  attack  of  a  human  foe,  but  against  those  of  tropical  insects, 
it  will  be  realised  that  the  provision  of  adequate  shelter  against 
these  pests  is  as  essential  as  the  provision  of  adequate  shelter 
against  the  fire  of  a  civilised  enemy  in  a  European  war.  The 
best  type  of  hut  or  barrack  is  one  raised  on  piles  from  the 
ground,  much  like  the  pattern  of  bungalow  used  in  Burma, 

Rations. — The  scale  of  rations  should  be  liberal.  The  meat 
would  perforce  need  to  be  in  most  cases  preserved,  and  probably 
biscuit  would  have  to  take  the  place  of  bread.  In  this  case  a 
liberal  supply  of  antiscorbutics  in  the  form  of  lime-juice,  pickles, 
jam  or  preserved  fruit  should  be  supplied.  A  special  issue  of 
coffee,  cocoa  or  tea  should  be  arranged  to  be  served  out  to 
men  on  night  duty.  It  is  unnecessary  to  say  that  alcoholic 
stimulants,  in  excess  of  the  ordinary  service  occasional  issue, 
are  not  demanded. 

Clothing. — The  ordinary  field  service  kit  would  be  sufficient, 
with  the  addition  of  gloves  and  veils  for  use  after  dark.  The 
Japanese  mosquito-bonnet  might  be  adopted. 

Special  equipment. — For  hospitals  mosquito-netting  should 
be  issued,  and  the  same  applies  to  the  details  left  at  the  base. 
It  is  doubtful  in  how  far  it  is  any  use  issuing  squares  of  curtain 
to  men  actually  in  the  field,  since  the  use  of  it  in  camp  life  is 
difficult.  It  would  at  least  be  a  harmless  precaution.  Some 
form  of  mechanically  operated  fan  should  be  supplied  for  use 
in  hospitals  and  offices  at  the  base.  The  motive  power  can  be 
supplied  either  by  electricity,  or  by  a  small  gas  or  hot  air 
engine.  Such  fans  not  only  aid  in  ventilation,  but  they  also 
assist  in  keeping  off  mosquitos. 

Instruction   of  men. — All  officers  and   men  taking   part   in 

Z  P 


594  THE    PREVENTION    OF   MALARIA   IN   WAR        [Sect. 

the  expedition  should  be  carefully  instructed  in  the  causation 
and  pathology  of  malarial  fevers,  as  well  as  of  other  tropical 
diseases.  The  important  part  played  by  insects  should  be 
pointed  out,  and  special  emphasis  should  be  laid  on  the  fact 
that  the  causation  of  these  diseases  is  not  of  an  esoteric  nature, 
but  the  mere  commonplace  result  of  the  bite  of  a  commonplace 
insect.  The  miasmatical  theory  dies  hard,  and  it  is  not  easy 
to  get  the  lay  intellect  to  realise  that  disease  is  not  caused 
by  some  mysterious  power  of  induction  possessed  by  some 
intangible  emanation.  The  period  occupied  or  spent  on  board 
ship  can  profitably  be  utilised  for  this  instruction. 

We  now  come  to  the  period  of  active  operations,  and  the 
first  point  to  be  considered  is  the  base  of  operations. 

Amongst  the  instructions  to  Sir  Garnet  Wolseley  in  1873 
it  was  laid  down  that  if  the  use  of  European  troops  became 
imperative  everything  should  be  prepared  in  anticipation,  and 
not  a  man  be  landed  before  the  moment  for  advance  into  the 
interior  arrived.  The  accommodation  for  troops  at  the  base 
need  not  therefore  be  large,  and  may  be  limited  to  that  for 
the  details  left  there  on  duty,  with  a  small  margin. 

Measures  directed  against  the  breeding-grounds  of  the 
mosquito,  which  should  have  been,  as  already  stated,  drawn  up 
by  the  special  medical  officer  entrusted  with  the  preliminary 
survey  of  the  base,  must  be  carried  out  as  in  cantonments  in  time 
of  peace.  A  specially  selected  medical  officer  should  be  placed 
in  charge  of  these  operations  with  executive  and  disciplinary 
powers,  a  step  that  has  been  proved  to  be  so  effective  by  the 
officers  of  the  United  States  Army  in  Cuba  and  elsewhere. 
This  officer  should  be  provided  with  an  ample  supply  of  native 
labour,  and  such  number  of  European  subordinates,  preferably 
N.C.O.s  of  the  Royal  Army  Medical  Corps,  as  the  size  of 
the  locality  demands.  Any  parsimony  in  this  direction  may 
have  serious  results.  Presumably,  the  base  will  not  be  in 
the  immediate  vicinity  of  a  native  village.  Nothing  but 
the    most    urgent    strategical    necessity    can    justify    such    ^ 


6o]  THE    BASE  595 

selection.  In  addition,  all  native  establishments  must  be 
encamped  or  hutted  at  a  distance  from  the  European  lines. 
Their  defence  and  discipline  must  be  ensured  by  appropri- 
ately situated  outposts,  electric  lights  and  barbed  wire  fencing 
being  used  to  assist  in  these  and  prevent  desertion.  The  guns 
of  the  fleet  can,  of  course,  assist  in  defence.  It  may  be  neces- 
sary to  erect  a  base  hospital,  but  patients  should  be  retained 
there  only  so  long  as  to  permit  of  rest  prior  to  embarkation. 
Two  hospital  ships  should  be  used  on  any  tropical  expedition. 
Of  these  one  would  always  be  available  for  the  reception  of 
sick  coming  from  the  front,  whilst  the  other  was  carrying  its 
passengers  to  the  nearest  healthy  port  or  island. 

It  is  essential  to  insist  that  there  is  no  difference  between 
the  conditions  at  the  base,  and  the  conditions  of  any  canton- 
ment during  ordinary  peace  time.  Everything  that  is  possible 
in  the  latter  case  is  possible  in  the  former,  and  should  be 
carried  out  with  the  same  thoroughness  and  the  same  careful 
organisation.  The  subject  of  prevention  of  malaria  in  canton- 
ments is  treated  of  elsewhere,  so  more  need  not  be  said  here. 
The  important  point,  and  this  cannot  be  too  often  repeated,  is 
that  undivided  responsibility  should  be  given  to  one  man,  and 
that  authority  of  equal  extent  should  go  hand  in  hand  with 
the  responsibility.  So  only  can  success  be  hoped  for  in  the 
war  against  malaria. 

Leaving  the  base  of  operations,  the  force  now  proceeds  on 
its  mission.  Detachments  will  no  doubt  be  made  from  time 
to  time  of  small  bodies  to  hold  fortified  posts  on  the  Lines  of 
Communication.  These  detachments  may  have  to  remain 
stationary  for  the  greater  part  of  the  campaign,  and  in  their 
case  regular  anti-mosquito  measures  must  be  undertaken,  as 
far  as  possible  on  the  same  lines  as  at  the  base,  or  in  canton- 
ments in  peace  time.  The  proximity  of  a  native  village  will 
necessarily  be  avoided  as  far  as  possible.  Where  the  tactical 
situation  necessitates  such  proximity,  the  village,  if  deserted, 
must  be  destroyed    by    fire  directly  the  permanent  occupation 


596  THE   PREVENTION   OF   MALARIA   IN   WAR        [Sect. 

of  the  post  is  decided  on.  If  still  inhabited  some  trouble  may 
arise,  but  it  would  be  preferable  to  forego  some  minor  tactical 
advantage  than  to  run  the  great  risk  of  disease  that  such  a 
situation  entails.  If  the  tactical  considerations  are  paramount, 
then  the  inhabitants  should  be,  if  possible,  evicted,  fresh  shelters 
being  built  for  them  at  a  little  distance,  and  any  necessary 
compensation  paid.  The  site  could  then  be,  as  already  recom- 
mended, cleansed  by  fire.  Since  it  may  be  accepted  that  the 
mosquitos  already  existent  in  the  neighbourhood  of  the  post 
are  infected,  it  would  be  advisable  to  adopt  the  method  origin- 
ally suggested  by  Nuttall  {^Journal  of  Hygiene^  1902,  vol.  ii.  p.  73) 
of  constructing  mosquito-traps  from  small  boxes,  lined  inside 
with  some  dark  material. 

Dr  Blin,  Principal  Medical  Officer  of  Conakry,  utilised  a 
similar  method  in  Dahomey  in  1905  {Archiv.  fur  Schiffs — 
und  Tropefi  Hygiene^  Bd.  xiii.,  1909,  p.  645).  He  noticed  there 
that  the  adult  insects  were  in  the  habit  of  sheltering  them- 
selves during  the  hot  hours  of  the  day  in  the  burrows  of  the 
land  crab,  and  in  holes  between  the  roots  of  mangroves.  He 
accordingly  caused  small  holes  to  be  dug  in  the  ground  about 
16  inches  deep,  at  a  somewhat  acute  angle  to  the  surface.  These 
holes  were  so  situated  as  to  be  protected  from  direct  sun- 
light, and  were,  if  properly  placed,  invariably  crowded  with 
mosquitos.  These  insects  remained  in  their  shelters  until 
4  P.M.  as  a  rule,  and  accordingly  between  2  and  3  p.m.  on 
each  day  the  holes  were  burnt  out  by  means  of  a  small  torch, 
consisting  of  a  stick  about  5  feet  long,  at  the  end  of  which  a 
piece  of  rag  or  tow,  soaked  in  petroleum,  was  fixed.  Such  a 
torch  will  burn  for  about  ten  minutes,  and  one  will  suffice  to 
burn  out  fifteen  to  eighteen  holes  if  in  close  proximity  to 
each  other.  A  well-trained  native  can  attend  in  this  manner 
to  one  hundred  mosquito-traps  in  a  day.  The  cost  is  trifling, 
3  litres  of  oil  are  sufficient  for  five  hundred  torches.  Fresh 
holes  must  be  dug  once  a  fortnight,  as  the  old  ones  become 
saturated  with   oil.     As   far   as   possible   all    permanent   posts 


6o]  THE    MARCH  597 

should   be   provided   with    mosquito  -  proof  huts,  and   in  their 
absence  mosquito-netting  should  be  supplied  to  the  men. 

Night  duties  should  be  reduced  to  a  minimum,  and  sentries 
relieved  every  hour,  or  even  oftener.  The  very  fullest  use 
should  be  made  of  mechanical  appliances,  barbed  wire  entangle- 
ments, searchlights,  etc.,  with  a  view  to  lessening  the  strain  on 
the  sentries.  Hot  coffee,  cocoa,  or  tea  should  be  freely  avail- 
able for  all  men  exposed  to  the  night  air.  On  no  account 
should  fatigues,  which  can  be  performed  by  natives,  and  for 
which  natives  are  available,  be  carried  out  by  Europeans.  The 
question  of  the  prophylactic  use  of  quinine  will  be  discussed 
later. 

With  regard  to  moving  bodies  of  troops,  which  do  not 
occupy  any  one  camp  for  more  than  forty-eight  to  seventy- 
two  hours,  it  is  obvious  that  measures  directed  against  the 
breeding-grounds  of  the  larvae  can  be  of  no  avail.  Before  any 
such  measures  can  have  effect  the  force  will  already  be  many 
marches  away.  The  defence  therefore  limits  itself  to  the  pro- 
tection of  the  men  from  the  adult  mosquito,  and  to  preventing 
the  access  of  the  latter  to  the  exposed  surfaces  of  the  body,  or, 
as  a  last  resort,  to  rendering  individuals  immune  to  the  Plas- 
modium by  the  use  of  quinine. 

The  former  can  be  achieved  by  the  use  of  mosquito-veils 
and  gauntlet  gloves  by  men  on  night  duty,  and,  doubtfully,  by 
the  use  of  mosquito  -  netting  when  asleep.  Unless  a  man  is 
provided  with  some  sort  of  framework  whereon  to  support  the 
curtain,  it  is  doubtful  in  how  far  this  precaution  is  of  use. 
Obviously  a  complete  set  of  poles  for  mosquito-curtains  cannot 
be  carried  by  each  man.  The  issue  of  a  couple  of  yards  of 
netting  to  each  member  of  the  force  is  at  the  same  time  a 
precaution  that  may  with  advantage  be  adopted.  The  use  of 
essential  oils  for  the  purpose  of  anointing  the  exposed  surfaces 
of  the  body  has  much  to  recommend  it.  It  causes  less  dis- 
comfort than  that  entailed  by  the  obstruction  to  respiration 
when  veils  are  worn.     There  is  at  the  same  time  less  hindrance 


598  THE   PREVENTION   OF   MALARIA   IN   WAR        [Sect. 

to  the  vision,  and  the  hands  are  less  hampered  in  the  manipula- 
tion of  the  fire-arm  than  is  the  case  with  gauntlet  gloves — 
important  points  in  the  case  of  sentries.  Kerosene  or  paraffin 
oil,  everywhere  procurable  in  the  tropics,  serves  this  purpose 
as  efficiently  as  any  of  the  more  elegant  aromatic  oils. 

Last  of  all  we  come   to  the  prophylactic  use  of  quinine. 
When  it  is  impossible  to  control  the  breeding  of  mosquitos,  or 
to  protect  oneself  from  the  bites  of  the  adult  mosquito,  then  it 
is  necessary  to  have  recourse  to  the  prophylactic  administration 
of  quinine.     But  it  must  be  premised   that  such  a  system  of 
prevention  of  malaria  is  a  confession  of  failure.     Success  may 
be  difficult,  or  even  impossible,   under  the    many  vicissitudes 
of  campaigning  in  tropical  jungles  when  troops  are  constantly 
on  the  move.     Success   may  be  difficult,  but  it  should  not  be 
impossible,   under    conditions    such   as    prevail    at   a   properly 
selected  and  administered  base  of  operations.     The  prophylactic 
administration  of  quinine  should  not  therefore  be  looked  upon  as 
anything  but  a  last  resort,  or  a   merely  temporary  expedient 
in   the   case   of  troops  living    under  settled    or   comparatively 
settled  conditions.     The  prevention  of  disease  by  the  adminis- 
tration of  drugs  is  as  unscientific  as  the  treatment  of  disease 
by  relief  of  symptoms  only.     Both  courses  may,  under  certain 
conditions,  be  imposed  on  us  by  the  force  majeure  of  circum- 
stances, but  neither  should  be  deliberately  chosen  as  the  chief 
method  of  defence,  either  in  sanitation  or  therapeutics.     The 
administration  of  quinine  has  this  great  drawback,  that  each 
individual  has  to  be  protected  separately.     The  total  mass  of 
disease   in  the   country  is  in   no  way   affected.      Every   new- 
comer is  still  exposed   to  the  risk  of  infection,  just  as  much 
as  his  predecessors,  and  each  such  person  must  be  protected. 
On  any  scientific  system   of  sanitation  the  disease  should  be 
attacked,   not    after    it   has    infected    the   patient,   but   before. 
Measures  directed  to  the  latter  end  protect  the  individual,  not 
the  community,  whilst  true  sanitation  aims  at  protecting  the 
individual  as  an   item   merely  in  the  community.     If  quinine 


6o]  QUININE  599 

is  administered,  I  lean  personally  to  the  German  method  of 
giving  two  large  doses  on  two  consecutive  days,  lo  to  15  grains, 
according  to  the  idiosyncrasy  of  the  individual.  As  a  matter 
of  practical  administration  this  should  be  done  once  a  week, 
on  Mondays  and  Tuesdays,  or  any  other  days,  but  the  same 
days  of  the  week  should  be  adhered  to  throughout.  The 
dose  is  less  likely  to  be  omitted  in  such  a  case. 


By   Major  C.   E.   P.   FOWLER 

Royal  Army  Medical  Corps,  Gibraltar 

61.  The  Prevention  of  Malaria  among  Troops  under  Peace 
Conditions.  —  The  vast  importance  of  malarial  fever  can  be 
appreciated  by  a  glance  at  the  following  table,  from  which  it 
will  be  seen  that  out  of  a  total  strength  of  European  troops 
serving  at  home  and  abroad  of  215,467  there  are  admitted  to 
hospital  each  year  19,092  patients  suffering  from  this  affection. 
The  average  constantly  sick  reaches  the  large  total  of  653'03, 
which  means  that  a  number  equal  to  the  ordinary  strength  of 
a  regiment  is  always  hors  de  combat  owing  to  this  disease. 

EUROPEAN   TROOPS  AT   HOME  AND  ABROAD. 
AVERAGE    STRENGTH,    215,467. 

Malaria. 


1908. 

Gross 

Admissions 

to 

Hospital. 

Deaths. 

Invalids. 

Average 

Constantly 

sick. 

19,092 

47 

197 

653-03 

1908. 

Ratio  per  i 

,000 

88-6 

0"2I 

1-87 

3-07 

1903- 

1907.     Ratio 

per  1,000 

64-4 

0-13 

2-39 

2-47 

The  next  table  shows  the  incidence  in  some  of  the  countries 
where  malaria  is  most  rife,  and  a  comparison  is  here  given 
of  the  effects  of  the  disease  during  1908  and  the  five  previous 
years. 

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6o2 


PREVENTION  OF  MALARIA  AMONG  TROOPS       [Sect. 


During  1908  malaria  gave  the  largest  gross  number  of 
admissions  and  therefore  the  highest  admission  rate  per  1,000 
of  any  disease  on  the  nomenclature.  This  fact  alone  must 
point  out  the  transcendent  importance  to  the  military  sanitarian 
of  finding  some  means  of  lessening  the  disease  and  saving  the 
enormous  waste  entailed  by  the  loss  of  service  of  our  soldiers 
and  sacrifice  of  public  money  through  inefficiency. 

On  looking  at  the  table  it  will  be  seen  that  Western  Africa 
heads  the  list  under  nearly  every  column  of  ratios  per  1,000. 
The  West  Coast  has  always  held  a  bad  record  for  malaria, 
and  this  disease  can  be  said  to  cause  from  50%  to  60%  of  the 
total  admissions,  invaliding  and  average  constantly  sick  for 
all  diseases  at  the  stations  in  this  command.  The  West  Indian 
troops  suffer  almost  as  severely  as  the  European,  but  the 
West  African  regiments  are  much  less  susceptible. 

The  country  which  costs  us  most  dearly  is  India,  where 
we  can  see  how  terribly  heavy  the  toll  of  sickness  caused  by 
malarial  fever  is.  The  figure  for  1907  was  a  great  improvement 
on  that  for  the  ten  years  previous,  but,  unfortunately,  1908 
was  a  wet  year,  fever  was  prevalent  amongst  the  native  popula- 
tion, and,  in  consequence,  the  figure  again  rose,  in  spite  of  all 

efforts  to  diminish  it. 

INDIA. 

APPROXIMATE  STRENGTH   OF   BRITISH  TROOPS,  70,000. 
Malarial  Incidence. 


Year. 

Admissions. 

Deaths. 

Invalids, 

1898. 

28,382 

50 

485 

1899. 

16,579 

36 

246 

1 900. 

19,445 

62 

190 

1901. 

18,217 

35 

418 

1902. 

15,367 

45 

245 

1903. 

17,037 

35 

244 

1904. 

12,112 

23 

259 

1905. 

7,947 

10 

126 

1906. 

12,601 

22 

136 

1907. 

10,662 

15 

274 

1908. 

16,763 

35 

62 

6i]  STATISTICS  603 

It  should  be  noted  that  since  1903  a  large  number  of  men, 
averaging  from  4,000  to  5,000  each  year,  are  treated  in  barracks. 

Amongst  the  native  army  of  India  malaria  is  also  very 
prevalent.  During  the  last  ten  years  the  average  strength  of 
these  troops  has  been  124,523,  of  whom  34,074  have  been  each 
year  admitted  to  hospital,  to  say  nothing  of  those  treated  in 
barracks  and  not  coming  on  the  returns. 

Having  thus  briefly  outlined  the  incidence  of  malaria  at 
some  of  the  various  stations  of  British  troops,  there  is  now  to 
be  considered  what  means  of  prevention  can  best  be  employed 
to  counteract  such  serious  losses.  In  the  first  place,  it  must 
be  presumed,  when  formulating  any  means  of  prevention,  that 
readers  are  believers  in  the  part  played  by  the  mosquito  in  the 
transference,  spread  and  maintenance  of  the  malarial  parasite, 
and  have  absolute  faith  in  the  formula  of  "  No  mosquitos,  no 
malaria."  It  would  appear  mere  waste  of  words  to  make  such 
a  statement  at  the  present  day,  were  it  not  that  experience 
has  shown  how  even  now  there  are  people,  including  members 
of  the  medical  profession,  who  still  retain  doubts  of  the  mosquito 
being  the  sole  carrier  of  the  malarial  parasite.  All  recom- 
mendations here  made  will  be  based  entirely  on  the  proved 
facts  of  malarial  transference  by  the  aid  of  certain  varieties 
of  Anophelines. 

In  formulating  the  measures  of  prevention  most  applicable 
to  troops,  it  must  always  be  remembered  that  the  soldier  cannot 
be  thought  of  in  his  position  as  a  unit  only  ;  there  also  has 
to  be  taken  into  consideration  the  inhabitant  of  the  country 
in  which  the  soldier  is  residing.  It  may  be  stated,  as  a  general 
axiom,  that  if  the  native  suffers  from  a  certain  disease,  it  will 
almost  necessarily  follow  that,  unless  extraordinary  precautions 
are  taken,  the  soldier  will  inevitably  suffer  from  a  like  com- 
plaint. The  soldier  is  largely  dependent  for  his  health  on 
that  of  the  community  around  him. 

Therefore  it  comes  to  this  in  many  cases,  that  to  check 
malaria  amongst  the  troops  it  will  be  necessary  at  the  same 


6o4  PREVENTION  OF  MALARIA  AMONG  TROOPS       [Sect. 

time  to  lessen  it  amongst  the  surrounding  inhabitants.  Thus 
the  question  can  be  seen  to  be  a  much  wider  one  than  would 
at  first  appear. 

Preventive  measures  may  be  divided  into  : — 

1.  General  measures  of  prevention. 

2.  Personal  measures  of  prevention. 

I.  The  general  measures  of  prevention  are  such  as  will 
be  undertaken  by  the  State,  Local  Government,  or  Community 
at  large.  As  a  rule  they  involve  a  considerable  expenditure 
of  capital,  as  well  as  a  large  amount  of  thought,  trouble  and 
probable  legislation  by  those  in  power.  For  these  reasons 
obvious  means  of  cutting  short  malarial  incidence  have  been 
on  more  than  one  occasion  allowed  to  lapse,  or  only  very  in- 
adequately provided  for  by  Local  Government  officials.  Failure 
must  necessarily  follow ;  and  though  the  authorities  may 
endeavour  to  make  a  scape-goat  of  the  means  recommended, 
the  blame  lies  entirely  at  their  own  door. 

In  other  instances  financial  considerations  alone  must  block 
the  way  to  improvement ;  and  in  certain  of  our  colonies  it  is 
a  question  for  serious  debate  whether  the  necessary  funds  should 
not  be  provided  temporarily  by  the  Imperial  Exchequer.  It 
is  heart-breaking  to  look  on  the  results  of  malarial  havoc, 
knowing  at  the  same  time  that  this  could  be  controlled,  were 
power  and  money  employed  to  the  best  advantage ;  and  yet 
neither  can  be  obtained. 

These  general  measures  can  be  dealt  with  but  briefly  in 
this  section,  but  reference  must  be  made  to  them  as  affecting 
the  population  surrounding  the  troops,  on  whose  health  the 
latter  are  so  largely  dependent. 

At  the  present  time  there  are  two  schools  of  opinion.  One 
relies  mainly  on  the  destruction  of  the  larval  mosquito ;  the 
other,  believing  that  such  a  desideratum  is  without  the  range 
of  possibility,  affirm  that  quinine  dosage  forms  the  mainstay 
of  prevention. 

The  first  school,  relying  chiefly  on  larval  destruction,  looks 


6i]  MEASURES  605 

upon  quinine  as  a  valuable  aid  certainly,  but  not  to  be  placed 
upon  the  same  footing  as  the  destruction  of  the  primary  agent, 
except  in  certain  cases  where  larval  destruction  is  almost  hope- 
less. The  second  school  base  their  preventive  measures  primarily 
on  quinine  dosage,  and  hold  that  if  the  malarial  parasite  is 
prevented  from  remaining  in  the  human  blood-stream  by  the 
administration  of  quinine,  then  it  is  impossible  for  the  mosquito 
to  become  infected. 

In  every  country  where  malaria  is  present  there  is  some 
diversity  of  opinion  on  which  of  these  methods  chief  reliance 
should  be  placed.  This  matter  will  be  dealt  with  fully  in 
other  sections,  so  that  no  further  reference  will  be  made  to 
it  here,  save  to  mention,  as  a  general  statement,  that  in  the 
majority  of  our  possessions  larval  destruction  is  the  one  of 
primary  importance  and  trial. 

A.  The  General  Measures  may  therefore  be  cited  as 
follows : — 

(i)  Larval  destruction. 

(2)  Segregation  of  the  soldier. 

(3)  General  quinine  treatment. 

(i).  Larval  destruction,  under  this  heading,  means  the 
elimination  of  all  spots  where  the  Anophelines  may  find  a  home 
or  a  suitable  breeding-place,  from  which  it  can  reach  barracks, 
cantonments  or  other  sites  where  troops  may  be  quartered. 
The  question  at  once  arises  :  What  is  the  probable  or  possible 
flight  of  one  of  these  insects?  A  reply  of  fact  and  not  of 
theory  it  is  impossible  to  furnish.  Some  years  ago  many 
authorities  would  have  judged  the  probable  limit  of  flight  at 
a  few  hundred  yards,  but  facts  have  arisen  since  then,  showing 
that  mosquitos  under  favourable  climatic  conditions  can  and 
will  travel  several  thousands  of  yards  from  their  breeding-place 
to  their  feeding-ground.  To  lay  down  a  precise  distance  of 
safety  is  quite  impossible,  but  a  reasonable  limit,  within  which 
no  breeding-spot  should  be  allowed  around  barracks,  may  be 


6o6  PREVENTION  OF  MALARIA  AMONG  TROOPS       [Sect. 

quoted  at  2,000  yards  or  thereabouts.  Now  many  of  our 
barracks  abroad  are  built  on  small  plots  of  ground  belonging 
to  the  War  Department,  but  the  land  closely  adjoining  may 
be  quite  without  their  jurisdiction  ;  the  consequence  being  that 
the  Military  Authorities  have  no  power  to  enforce  the  abate- 
ment of  evils  existing  on  the  ground  of  neighbouring  tenants. 

At  the  present  day  no  barracks  should  be  built  in  the 
tropics  or  sub-tropics  on  ground  which  does  not  include  the 
control  of  an  area  of  2,000  yards'  radius  from  it  as  the  centre 
of  a  circle.  Unless  this  plan  is  carried  out  the  troops  occupy- 
ing the  barracks  must  of  necessity  be  exposed  to  all  dangers 
arising  from  a  neglected  condition  of  the  surrounding  area,  as 
well  as  the  risk  of  being  infected  with  other  diseases  from 
which  the  inhabitants  living  on  this  ground  may  be  suffering. 
Many  examples  of  barracks  situated  in  this  faulty  position 
might  be  quoted  from  our  Colonial  garrisons. 

When  the  State  or  War  Department  owns  or  controls 
the  land  around  barracks,  it  is  incumbent  upon  them  to  place 
this  ground  in  such  a  condition  that  it  shall  not  act  as  a 
breeding-spot  for  mosquitos. 

If  such  a  land  is  not  their  property,  and  is  forming  a  favour- 
able source  of  origin  for  Anophelines,  it  is  essential  that  the 
ground  should  be  purchased,  in  order  to  gain  complete  control 
over  it.  The  purchase  may  involve  great  expense,  but  this 
would  probably  soon  be  covered  by  the  saving  effected  in  the 
improved  sick-rate  of  the  troops. 

(2).  Segregation  of  the  soldier. — This  has  been  referred  to 
under  the  previous  heading.  It  may  be  stated  fairly  con- 
clusively that  the  wider  the  separation  of  the  soldier  from  the 
native  inhabitants  the  better  will  be  his  health.  The  barracks 
that  have  been  carelessly  placed  in  the  midst  of  native  towns, 
or  that  have  become  encroached  upon  and  surrounded  by 
native  houses,  will  show  a  far  heavier  incidence  of  disease  than 
barracks  standing  in  isolated  positions.  The  reservoir  of  the 
malarial  parasite  is  to  be  found  chiefly  in  the  children  of  the 


6i]  CANTONMENTS  607 

native  inhabitants.  An  infected  village  with  a  high  spleen 
rate  amongst  its  children  will  contaminate  any  camp  or  settle- 
ment within  a  wide  distance  of  its  site.  Such  a  condition  of 
things  exists  in  numbers  of  our  garrisons  abroad. 

Take  the  case  of  so  many  of  our  Indian  stations.  The 
barracks  may  have  originally  been  placed  at  a  reasonable 
distance  from  the  native  town,  but  a  bazaar  has  been  allowed 
to  grow  up  alongside  them  for  the  use  of  servants  and  others 
serving  on  or  trading  with  the  troops.  Many  of  these  Sudder 
Bazaars  contain  several  thousands  of  inhabitants.  Malaria  or 
any  other  disease  from  which  they  may  suffer  must  inevitably 
spread  to  the  troops. 

Again,  within  the  Indian  cantonment,  until  quite  recently 
the  native  was  allowed  to  grow  any  sort  of  crop,  and  to  do 
practically  whatever  he  wished  with  the  ground  rented.  The 
consequence  was,  and  still  is,  in  some  places,  that  rice  fields 
existed  within  quite  a  short  distance  of  barracks,  to  say  nothing 
of  other  crops  requiring  an  abundance  of  moisture,  which  so 
generally  means  neglected  ditches  and  the  formation  of  small 
marshes.  The  outcry  against  the  continuance  of  such  a  state 
of  things  has  often  been  raised,  but  is  invariably  met  by  the 
answer  that  if  such  crops  are  done  away  with,  the  cantonment 
funds  would  disappear  and  financial  ruin  ensue.  It  is  the  duty 
of  the  State  to  insist  on  an  abatement  of  such  dangers;  and  if 
in  any  case  its  continuance  cannot  be  stopped,  then  the  troops 
should  be  moved  and  the  station  evacuated.  Until  the  State 
can  appreciate  the  enormous  losses  involved  by  the  sickness  of 
our  soldiers  from  malaria  and  its  sequelae,  it  is  almost  hopeless 
to  expect  works  to  be  taken  in  hand,  which  must  appear  to  the 
authorities  to  involve  a  large  expenditure  of  capital  without  any 
evident  financial  return. 

(3).  General  quinine  treatment. — By  this  is  meant  quinine 
treatment  of  the  general  population  of  the  country  in  districts 
around  the  location  of  troops.  This  lies  outside  the  measures 
to  be  undertaken  by  the  Military  Authority,  who  would  only 


6o8  PREVENTION  OF  MALARIA  AMONG  TROOPS       [Sect. 

be  in  a  position  to  advise  and  not  insist  on  such  a  campaign 
of  defence.  It  would  mean  action  on  the  lines  of  the  Italian 
school,  and  will  be  fully  dealt  with  in  another  section.  The 
military  forces  would  benefit  very  greatly,  as  the  chief  source 
of  their  contamination,  namely,  the  native  children,  would  be 
brought  under  treatment,  and  their  capability  of  spreading  the 
parasite  by  acting  as  reservoirs  materially  lessened. 

B.  Personal  Meastires  of  prevention  must  now  be  considered. 
These  are  such  as  can  be  carried  out  by  units  themselves  and 
will  involve  no  great  initial  expense,  as  is  so  often  the  case  with 
the  general  measures. 

The  various  means  employed  may  be  enumerated  as 
follows : — 

(i)  The  attack  on  Anopheline  larvae  in  their  breeding  spots. 

(2)  The  defence  against  the  adult  Anopheline. 

(3)  The  segregation  of  malarial  patients,  and  their  protec- 

tion from  the  Anopheline  mosquito. 

(4)  Segregation  from  the  native. 

(5)  The  administration  of  quinine. 

(i).  It  is  one  of  the  first  duties  of  an  officer  commanding 
a  barrack  or  cantonment  to  see  that  the  same  is  kept  in  a 
clean  and  sanitary  condition.  It  must  also  be  the  duty  of 
this  officer  to  see  that  the  place  under  his  control  in  a  malarious 
country  is  in  such  a  state  that  mosquitos  will  be  unable  to  find 
any  breeding  spots  on  its  area.  If  he  does  not  himself  under- 
stand or  appreciate  the  hygienic  importance  of  this  order, 
he  must  be  compelled  to  do  so  by  a  higher  authority,  and 
be  made  to  accept  the  advice  of  experts  who  have  made  a 
special  study  of  the  subject. 

The  attack  on  mosquito  larvae  can  best  be  carried  out 
by  the  formation  of  "  mosquito  brigades,"  or  "  working  gangs," 
consisting  of  men  especially  trained  to  such  work.  These 
men   may   be   either   soldiers   or   natives   of  the   country.     It 


6i]  MOSQUITO   REDUCTION  609 

is  not  considered  that  the  former  are  suitable  for  these  duties. 
Soldiers  are  wont  to  despise  such  employment,  and  think  it 
beneath  their  dignity  to  carry  it  out.  In  addition,  there  is 
always  the  likelihood  of  their  being  continually  changed  and 
taken  for  other  duties,  just  at  a  time  perhaps  when  their  services 
are  most  urgently  required. 

It  must  also  be  borne  in  mind  that  the  heaviest  work  will 
come  just  at  the  most  trying  season  of  the  year,  when  the 
weather  is  intensely  hot  and  perhaps  saturated  with  moisture. 
In  a  tropical  country  soldiers  should  certainly  not  be  employed. 

It  remains,  then,  to  rely  on  the  native.  It  has  been  found 
in  practice  that,  if  the  proper  class  of  native  is  selected,  he  is 
capable  of  being  trained  very  efficiently  to  the  work  ;  but 
of  course  he  will  always  need  the  supervision  of  Europeans. 
The  number  of  these  men  required  v/ill  vary  in  accordance 
with  the  size  and  conditions  of  the  barracks,  cantonment  or 
War  Department  ground.  Experience  has  shown  that  it  is 
better  to  divide  up  the  men  into  separate  units  or  working 
gangs,  rather  than  have  a  number  of  men  engaged  indis- 
criminately. A  convenient  working  gang  would  consist  of 
a  head  man  with  two  or  three  underlings.  The  head  men 
should  be  selected  for  their  special  aptitude  in  the  work  and 
should  receive  more  instruction  than  their  underlings,  in  order 
that  they  in  their  turn  may  be  able  to  impart  the  information 
received.  All  the  men  employed  must  be  given  a  general 
insight  into  the  causation  of  malaria  and  be  taught  the  life 
history  of  the  mosquito.  They  must  know  the  different  species, 
both  of  the  larvae  and  adults,  together  with  their  habits.  They 
must  also  receive  a  course  of  instruction  in  the  best  means  of 
dealing  with  casual  water,  in  ditching  and  rough  draining. 
These  men  should  be  under  the  direct  control  of  the  medical 
or  other  officer  appointed  in  charge  of  malarial  work,  and 
he  will  be  responsible  for  their  instruction. 

Different  ways  of  working  the  gangs  can  be  arranged  as 
best  suits  the  individual  place.    For  instance,  the  station  may  be 

2Q 


6io  PREVENTION  OF  MALARIA  AMONG  TROOPS      [Sect. 

divided  up  into  six  different  areas,  and  a  gang  made  responsible 
for  each  ;  or  gangs  can  be  employed  on  one  of  these  areas  for  a 
day  in  each  week.  Again  a  gang  may  be  appointed  to  each 
regiment  or  unit,  and  a  man,  preferably  a  N.C.O.,  made  respon- 
sible for  its  working.  The  general  duties  of  these  gangs  will  be 
shortly  as  follows  : — The  exploring  and  examining  of  all  ground 
around  the  barracks  or  cantonment ;  the  collection  of  all  tins, 
pots,  pans,  or  other  rubbish  capable  of  holding  water ;  the 
cutting  and  removal  of  all  waste  vegetation,  brushwood 
and  scrub ;  the  clearing  and  grading  of  ditches,  the  filling 
up  of  holes  and  hollows,  the  draining  away  of  casual  water 
and  small  marshes  ;  the  examination  of  water-tanks,  water- 
butts,  wells  and  cess-pools  ;  the  search  for  plants  and  holes 
in  trees  retaining  water ;  the  treating  with  paraffin-oil,  tar  or 
other  larvicide  of  all  water  that  cannot  be  disposed  of  or 
properly  protected. 

It  is  advisable  that  attention  should  be  paid,  not  only  to 
the  Anopheline  larvae,  but  also  to  those  of  Culex  and  Stegomyia, 
as  the  destruction  of  the  two  latter,  which  are  usually  the  more 
domestic  species  and  therefore  more  in  evidence  as  nuisances, 
will  show  the  inhabitants  of  the  station  that  something  is  being 
done.  Besides,  in  many  places,  these  mosquitos  are  a  veritable 
pest,  the  Stegomyia  by  day  and  the  Culex  by  night,  and  their 
destruction  is  worth  some  outlay,  if  only  to  obtain  increased 
comfort. 

When  dealing  with  these  larvicidal  operations,  the  question 
of  the  station  or  cantonment  irrigation  is  certain  to  arise.  Where 
a  canal  supply  is  in  force,  as  in  many  parts  of  India,  it  is  well- 
nigh  impossible  to  act  efficiently  on  the  Anopheline  larvae, 
unless  such  irrigation  is  stopped.  The  main  canal,  as  it  passes 
through  the  cantonment,  is  broken  up  into  numberless  small 
channels  for  the  distribution  of  the  water.  These  generally 
become  little  better  than  rough  and  neglected  gutters,  over- 
grown with  vegetation,  and  allowing  the  water  to  stagnate. 
Small  patches  of  marsh  or  water-logged  soil  are  often  formed 


6i]  MECHANICAL  PROTECTION  6ii 

by  the  side  of  these  channels  from  leaking  or  overflowing  of 
their  banks.  These  will  form  ideal  breeding  spots  for  most 
varieties  of  the  Anophelines.  On  the  other  hand,  it  has  to  be 
recognised  that  if  irrigation  is  cut  off,  the  cantonment  will  be 
turned  into  a  desert.  Irrigation  from  wells  is  by  no  means  so 
objectionable.  The  supply  of  water  is  limited  by  the  labour 
necessary  to  raise  it  from  the  well,  and  therefore  only  a 
sufficient  quantity  to  irrigate  the  crops  themselves  is  drawn. 
Water  seldom  stands  wasting  in  channels  or  sides,  so  that 
the  Anophelines  have  little  opportunity  of  finding  any  breeding 
pools. 

A  medical  officer  should  be  detailed  for  each  station  or 
cantonment  to  look  after  all  malaria  work,  and  he  should  be 
placed  in  charge  of  all  the  working  gangs  to  direct  and  super- 
vise their  operations. 

At  the  headquarters  of  each  district  or  province  a  medical 
officer  possessing  special  knowledge  on  the  subject  of  malaria 
should  be  appointed.  It  should  be  his  duty  to  travel  from 
place  to  place,  to  supervise  the  work  being  carried  on,  and  to 
advise  as  to  future  procedures.  All  reports  on  malaria  from 
the  out-stations  should  be  submitted  to  him,  in  order  that  he 
may  collect  the  various  details,  and  be  in  a  position  to  form 
a  reliable  opinion  on  the  efficiency  or  otherwise  of  the  different 
measures  of  prevention. 

(2).  The  defence  against  the  adult  Anopheline. — The  means 
at  disposal  are  mosquito-proof  houses  and  mosquito-curtains. 

In  Europe,  or  even  in  a  sub-tropical  climate  it  is  easy  to 
lay  down  rules  and  carry  them  out  as  regards  the  use  of  the 
above  means.  The  matter  resolves  itself  into  one  only  of 
expense  for  their  provision.  In  the  tropics  the  situation  is 
far  different.  Here  the  most  prominent  question  is :  Will  the 
troops  or  others  make  use  of  such  means  if  they  be  provided? 
or  even  it  may  be  asked  :  Can  they  be  allowed  to  do  so .?  To 
those  who  have  experienced  hot  weathers  on  the  plains  of  India 
this  point   is  one  that  is  only   too  vividly   appreciated.      To 


6i2  PREVENTION  OF  MALARIA  AMONG  TROOPS        [Sect. 

expect  any  one  to  remain  under  a  mosquito-net  during  the  day 
or  night-time  of  the  hot  weather,  or  even  to  remain  in  a  room, 
the  windows  of  which  are  blocked  by  wire -gauze  netting,  is 
scarcely  reasonable.     Existence  would  be  unbearable,  and  in 
all  probability  sacrificed  to  an  attack  of  heat  apoplexy.     Un- 
fortunately the  use  of  mosquito  -  curtain  and  punka  is  incom- 
patible, at   least  for  the  soldier.     Mosquito  -  proof  rooms  and 
powerful  electric  punkas  or  fans  might  be  borne.      In   many 
parts  of  India,  for  five  or  even  six  months  of  the  year,  punkas 
are  a  necessity  of  existence,  and  therefore  curtains  cannot  be 
made  use  of       It  is  impossible  to  lay  down  definite  rules  in 
regard  to  this  question.     In  each  district  or  station  the  various 
points  will  have  to  be  taken  into  consideration  in  a  common- 
sense    manner,    and     corresponding    recommendations     made. 
Mosquito  -  curtains   should    undoubtedly   be   provided   for   all 
soldiers   in   a    malarious    locality,   and   they   should    be    made 
to  use  them  if  the  climatic  conditions  permit.      The  form   of 
curtain  varies.     The  bell  pattern  is  the  cheaper,  more  easily 
managed   and  hung,  but   does  not  allow   the   same   air-space 
within  it.     This  appears  a  minor  point  in  the  sub-tropics,  but 
is  soon  appreciated  under  tropical  conditions.     The  old  pattern 
square  shape  is  now  again    being  used   on    this  account,  but 
the  obstruction  to  ventilation  and  air  movement  becomes  very 
great  when  each   bed  in   a  barrack  room   is  fitted  with  these 
curtains.     Men  must  always  be  instructed  in  the  best  method 
of  hanging  them,  otherwise  they  are  worse  than  none  at  all, 
and  act  simply  as  traps.     In  many   cases  it  has  been  found 
that  although  curtains  are  provided,  the  men  are  not   in  the 
habit  of  using  them   when  on   guard  or   attached    duty,   and 
consequently  become  infected.      The  provision  of  wire-gauze 
for  all  doors,  windows  and  ventilators  in  a  barrack  -  room   is 
one    of    theoretical    excellence,    but    one    of    great    practical 
difficulty.     The  expense,  both  initial  and  recurring,  is  of  some 
magnitude,  and  constant  watch   must  be  kept  on  the  proper 
fitting  and   closing  of  the  openings ;  otherwise  the  soldier  is 


6i]  SEGREGATION  613 

sure  to  remove  what  he  will  consider  are  useless  obstructions 
to  the  breeze. 

In  certain  isolated  and  dangerous  positions,  where  a  small 
number  of  men  are  on  duty,  the  employment  of  this  method 
is  undoubtedly  a  sound  one,  but  as  a  general  preventive 
measure  it  has  not  been  taken  up  for  our  garrisons. 

As  regards  the  destruction  of  the  adult  mosquito  but  little 
can  be  done.  The  majority  of  the  Anophelines  are  night 
feeders,  and  as  a  general  rule  will  leave  a  room  before  day- 
light. There  are  some  varieties,  however,  which  will  remain 
a  certain  time  after  engorgement,  and  can  be  found  in  the 
dark  corners  of  rooms.  Various  means  have  been  devised  for 
killing  off  these  insects  by  fumigation,  such  as  the  burning 
of  sulphur,  formalin  or  other  chemicals.  These  methods  are 
of  but  little  use  in  the  tropics,  where  it  is  most  difficult  to 
render  a  room  in  any  way  fume-tight.  The  safest  procedure 
consists  of  the  regular  sweeping  out  of  all  dark  corners,  removal 
of  unnecessary  hangings,  and  thorough  cleanliness.  Many 
so-called  specifics  have  been  brought  forward,  purporting  to 
ward  off  the  attacks  of  mosquitos  when  smeared  on  the  skin, 
such  as  soaps,  ointments,  oils,  etc.  Some  of  these  are  excellent, 
whilst  their  virtue  lasts,  but  the  latter  is  very  evanescent,  and 
few  of  them  are  found  to  be  efficient  for  more  than  about  half 
an  hour. 

(3).  The  segregation  of  malarial  patients  and  their  protection 
from  Anophelines. — This  is  a  most  important  matter  and  one 
that  has  been  much  neglected  up  till  very  recently.  It  was 
customary  to  place  patients  suffering  from  malaria  in  any 
ward  with  other  patients  not  yet  infected,  no  provision  being 
made  or  even  thought  of  to  prevent  infection  being  carried 
from  one  to  the  other.  In  consequence,  many  men  who  were 
in  hospital  for  some  trivial  complaint  became  infected  with 
the  parasite  during  their  detention.  At  the  present  day 
it  is  understood  that  a  patient  suffering  from  malaria  is  a 
danger  to  his  non-infected  neighbour,  and  he  should,  therefore. 


6i4  PREVENTION  OF  MALARIA  AMONG  TROOPS       [Sect. 

be  placed  in  a  separate  ward,  and  provided  with  curtains,  or 
if  these  cannot  be  borne,  then  the  ward  must  be  rendered 
impervious  to  the  entrance  of  the  mosquito.  In  any  station 
where  malaria  is  prevalent,  these  precautions  are  essential. 
A  ward  containing  malarial  patients  unprotected  from  the 
attacks  of  the  Anopheline  carrier,  is  a  grave  potential  danger 
to  the  surrounding  community,  and  should  not  for  one  moment 
be  tolerated. 

(4).  Segregation  from  the  native. — The  importance  of  this  has 
been  referred  to  previously  under  general  measures  of  preven- 
tion, when  insistence  was  laid  on  the  advantages  to  be  derived 
in  separating  soldiers  entirely  from  the  native  houses  and 
population  around.  It  must  not  be  forgotten  that  the  soldier 
may  still  easily  contract  the  disease  by  visiting  places  or 
towns,  where  malaria  is  rife  amongst  the  inhabitants,  and  it 
is  very  necessary  to  do  everything  in  one's  power  to  prevent 
such  excursions,  more  especially  after  dark. 

When  troops  attend  camps  of  exercise  or  are  on  the  march 
through  a  malarious  country,  the  encampments  should  always 
be  placed  as  far  as  possible  from  any  native  village  or  from 
any  spots  where  infected  mosquitos  are  likely  to  be  prevalent. 
The  same  advice  can  be  given  as  regards  shooting-trips,  on 
which  the  officer  often,  and  the  soldier  occasionally,  proceed. 
Native  guides  will  always  try  to  induce  a  party  to  pitch  their 
encampment  in  close  proximity  to  a  village  or  water  of  some 
kind,  for  obvious  reasons  of  supply.  This  should  not  be 
allowed,  but  the  very  opposite  plan  adopted.  The  use  of 
nets  for  soldiers  when  on  the  march  is  almost  impossible, 
crowded  as  they  are  together  in  small  tents,  but  for  the  officer 
it  is  quite  a  simple  matter  to  carry  a  small  bell-shaped  net 
and  sling  it  up  from  the  tent  wall  or  branch  of  a  tree  at  night. 
On  shooting-trips  during  the  malarious  season  a  net  should 
invariably  be  carried.  It  is  very  light  and  easily  packed,  if 
the  supporting  ring  is  hinged  to  fold  over. 

(5).   The   administration   of  quinine.  —  This   drug  must  be 


6i]  QUININE  615 

employed  for  the  soldier  as  for  the  general  population,  namely, 
to  (a)  cut  short  the  actual  attack,  (d)  prevent  relapses,  (c) 
prevent  the  infected  acting  as  reservoirs  and  potential  spreaders 
of  the  parasite,  (d)  act  as  a  prophylactic  agent. 

(a)  The  various  methods  of  administering  quinine  as  a 
curative  agent  will  be  dealt  with  in  other  sections, 
so  that  further  reference  to  this  point  will  not  be 
made.  The  treatment  of  the  soldier  differs  in  no 
way  from  that  of  a  man  in  civil  life,  and  army 
medical  officers  have  now  a  free  choice  of  any 
method  which  they  may  select. 
(3)  It  may  be  taken  for  granted  that,  if  a  patient  has 
been  infected  with  the  malarial  parasite  and  suffered 
from  an  attack  of  fever  thereby,  it  will  require  a 
period  of  probably  three,  certainly  two  months 
continuous  and  rigid  treatment,  before  the  parasite 
is  rendered  more  or  less  inactive.  To  say  that  it 
is  destroyed  is  not  possible,  however  energetic  the 
treatment  may  be. 

The  failures  of  quinine  to  prevent  so-called 
relapses  are  not  generally  failures  in  the  true  sense, 
as  the  recrudescence  of  the  attacks  is  in  the  larg-e 
majority  of  such  cases  due  to  a  re-infection.  This 
is  the  reason  why  it  is  so  extremely  difficult  to  cure 
a  patient  when  he  still  continues  to  reside  in  a 
malarious  locality.  Within  the  last  few  years  the 
importance  of  the  after-treatment  of  all  soldiers 
affected  with  malaria  has  been  appreciated  by 
army  medical  officers,  and  nowadays  every  care  is 
taken  to  carry  on  continuous  treatment  over  a  period 
of  several  months  and  to  record  results. 

It  may  be  presumed  that  the  blood  of  every 
suspicious  case  of  fever  now  admitted  to  a  military 
hospital  will  be  examined  for  the  malarial  parasite, 


6i6  PREVENTION  OF  MALARIA  AMONG  TROOPS       [Sect. 

and  that  the  diagnosis  of  malaria  will  never  be 
made  unless  a  positive  result  is  found.  When  a 
malarial  patient  is  discharged  from  hospital,  some 
such  scheme  as  the  following  may  be  employed. 
The  man  is  given  a  paper,  telling  him  on  what 
days  he  must  attend  for  doses  of  quinine.  A 
duplicate  of  this  order  is  kept  by  one  of  the 
hospital  staff,  whose  duty  it  is  to  give  the  paper, 
note  the  dates  of  attendances,  and  report  any 
failure  to  do  so. 

The  raison  d'etre  of  continued  treatment  should 
always  be  briefly  and  reasonably  explained  to  the 
patient,  in  order  that  he  may  grasp  the  importance 
of  taking  quinine  regularly,  not  only  for  his  own 
sake  but  in  the  interest  of  his  comrades.  The 
treatment  must  be  enforced ;  but  as  a  general  rule 
there  is  not  much  difficulty  in  making  a  soldier 
who  has  once  had  an  attack  of  malaria  realise 
that  it  will  be  to  his  benefit  to  continue  treatment. 
Every  facility  must  be  given  to  him  for  obtaining 
the  necessary  doses. 

There  is  some  variance  of  opinion  as  to  the 
best  method  of  giving  the  drug.  For  soldiers  the 
most  suitable  plan  is  perhaps  the  administration  of 
lo  or  15  grains  of  the  sulphate  or  its  equivalent 
on  two  successive  days  every  week  or  on  three 
successive  days  every  ten  days  over  a  period  of 
three  months.  During  this  time  the  blood  should 
occasionally  be  examined  for  the  presence  of  para- 
sites and  the  treatment  modified  if  necessary. 
{c)  To  prevent  the  infected  acting  as  reservoirs  of  the 
parasite :  Treatment  for  this  object  is  in  reality 
bound  up  with  that  mentioned  for  the  prevention 
of  relapses.  If  the  latter  do  not  occur,  it  is 
improbable  that  many  or  in  fact  any  gametes  are 


6i]  QUININE  617 

circulating  in  the  patient's  blood.  Similar  lines 
of  giving  quinine  can  therefore  be  recommended. 
{d)  As  a  prophylactic  agent :  On  the  use  of  quinine  for 
this  object  there  is  a  considerable  diversity  of 
opinion,  and  the  latest  military  reports  are  not  by 
any  means  favourable  to  any  definite  conclusions  of 
the  benefit  ensuing  from  its  administration,  (A.M.D. 
Report,  1908,  India.) 

However,  there  has  been  undoubted  evidence  of 
beneficial  action  exerted  by  its  use,  and  it  is  therefore 
the  duty  of  the  medical  officer  in  charge  of  troops  to 
administer  the  drug  whenever  malarial  conditions  are 
widely  prevalent.  It  must  always  be  remembered 
that  positive  results,  as  the  outcome  of  quinine  in 
prophylactic  dosage,  are  most  difficult  to  estimate. 
Negative  results  are  declared  only  too  vividly  ;  and 
a  few  of  the  latter  as  facts  far  outweigh  any  estima- 
tions of  the  former  as  theories.  In  considering  the 
results,  it  should  be  also  brought  to  mind  that  a  large 
proportion  of  the  cases  admitted  to  hospital,  probably 
more  than  50%  in  some  stations,  are  relapses,  and 
that  the  administration  of  quinine  may  greatly  lessen 
the  number  of  such  relapses,  quite  apart  from  any 
action  in  preventing  fresh  infections. 

The  difficulties  encountered  in  carrying  out  an 
efficient  prophylactic  issue  are  very  great.  The 
soldier  is  extremely  suspicious,  when  forced  by  order 
to  undergo  such  a  dosage,  and  will  often  do  every- 
thing in  his  power  to  evade  it.  Considerable  tact 
must  always  be  employed  in  order  to  win  over  his 
confidence.  In  any  case  the  drug  must  be  taken  by 
order,  and  in  the  presence  of  the  medical  officer  or 
other  reliable  person.  An  issue  to  volunteers  only 
soon  resolves  itself  into  a  farce. 

The  drug  may  be  given  in  solution,  or  in  the 


6i8  PREVENTION   OF   MALARIA  AMONG   TROOPS     [Sect. 

form  of  pills  or  tabloids.  Solution  has  the  advantage 
that  it  is  always  at  hand  and  easily  made  up,  but 
the  taste  is  of  course  extremely  disagreeable  to  most 
people.  Pills  are  convenient,  but  take  some  time 
to  make,  and  do  not  keep  well  under  conditions  of 
heat  or  moisture.  Tabloids  are  really  the  most 
useful  form,  and  given  as  a  preventative  only,  they 
are  unlikely  to  pass  through  the  intestine  unchanged. 
The  uncoated  form  should  be  used.  As  regards 
this,  there  is  a  note  in  the  A.M.D.  Report,  1908,  to 
the  following  effect.  "  As  is  usual  the  men  disliked 
the  quinine  parades,  and  many  adopted  every  means 
they  could  to  avoid  swallowing  the  dose ;  tabloids  of 
quinine  were  found  unsuitable,  since  many  men  kept 
them  in  their  mouths  until  the  parade  was  dismissed, 
and  then  threw  them  away.  Hence,  quinine  in 
solution  was  administered,  and  each  man  had  to 
shout  out  his  regimental  number  immediately  after- 
wards to  prove  that  the  dose  had  been  swallowed." 

The  above  is  one  typical  instance  of  resentment  at  com- 
pulsory treatment,  and  points  out  how  extremely  difficult  it 
must  be  to  rely  entirely  on  the  results  of  quinine  prophylaxis 
under  military  conditions. 

As  regards  the  dose,  there  is  some  difference  of  opinion. 
A  daily  administration  of  5  grains  cannot  be  recommended  for 
soldiers,  owing  to  the  trouble  it  involves  in  the  parading,  etc., 
of  the  men.  In  India  during  1908,  where  in  53  out  of  58 
plains  stations  quinine  was  given  as  a  prophylactic  during  the 
malarious  season,  in  the  majority  of  the  cases  10  to  15  grains 
were  used  on  two  consecutive  days  in  each  week.  This  seems 
to  be  as  good  a  method  as  can  be  recommended. 

One  most  important  point  not  yet  referred  to  is  the  instruc- 
tion of  the  soldier  and  others  in  the  causation  and  spread  of 
malaria. 


6i]  INSTRUCTION  619 

All  such  instruction  should  be  given  in  a  way  which  will 
appeal  to  the  imagination,  and  the  language  used  should  be 
couched  in  the  most  popular  style.  Short  descriptions  of 
lantern  slides  are  the  very  best  means  of  imparting  elementary 
knowledge  of  this  kind.  Each  medical  officer  appointed  to  a 
division  or  district  as  an  expert  on  malaria  should  be  provided 
with  a  set  of  lantern  slides  and  suitable  lantern,  and  give  short 
demonstrations  in  each  station  throughout  his  district.  A  full 
but  elementary  understanding  of  the  cause  of  malaria  and  the 
role  of  the  mosquito  in  its  spread,  will  explain  to  the  soldier  the 
reason  of  many  precautions  which  he  may  have  failed  to  under- 
stand and  thereby  neglected. 

It  will  be  found  that  the  men  are  ready  enough  to  receive 
such  instruction,  and  become  greatly  interested  in  the  subject, 
provided  that  the  facts  are  placed  in  a  simple  and  straight- 
forward manner  before  them. 


^' 


2.    THE    CAUSK    Ul'    llIK    MALARIA    A.\I().\(,ST    TH1-:    TK(JU1'S    IN    Till-;    lU'TS. 

This  stream  was  situated  at  a  distance  of  400  yards,  and  formed  a  most  favourable 
breeding-ground  for  /-".  coslalis. 


3-   ANoi'iiEi.iNK  hkki-:i)1n(;-(;k()i;.\I)  in   a  coi.oniai,  cantoxment  (Mal-ritil-s). 


(The  Latanier,  near  Port  Louis,  Mauritius— the  river  of  Paul  and  \'irginia. — R.  Ross. 


5.    TIIK   SAME    FINISHKI). 

This  stood  intact  after  several  floods. 


*■     't  *'         ^  c  \ 


ADDENDA 
62.  Sugfgrested   Terminologry  for  the  Phenomena  of  Cyto- 

gfenesis. — Several  such  terminologies  have  been  proposed,  among 
others  by  myself.  That  of  F.  Schaudinn  is  now  extensively  used,  but 
has  the  defect  of  attempting  to  limit  the  word  spore  to  the  first  genera- 
tion of  daughter  cells  proceeding  from  the  zygote,  and  the  word  schist 
only  to  subsequent  generations.  His  merozoites  are  in  fact  spores,  his 
spores  merozoites  :  his  spores  are  really  produced  by  his  schizogony  and 
his  schizonts  by  his  sporogony.  I  think  therefore  that  a  more  general 
system,  in  which  each  root  is  invariably  used  in  a  strictly  defined  sense, 
may  still  be  proposed  for  consideration,  briefly,  as  follows  : — 

Schist  =^z.  division  of  the  centrosome  and  nucleus  only. 

Clast  =  a.  division  of  centrosome,  nucleus  and  cytoplasm  only. 

Mere  =  2L  division  of  the  whole  cell. 

Spore  =  z.  mere  when  more  than  two  meres  are  produced  at  a  time. 

Protoschists  or  protoclasts  are  the  first  schists  or  clasts  produced  in  the 

dividing  cell,  z.w^  protomeres  ox  protospores  the  first  meres  or  spores 

(starting  with  the  zygote). 
Deutero-  and  trito-^  etc.,  for  succeeding  generations. 
Gametes  =  the   sexual   elements.     Microgamete  =  sperm,    macrogamete  = 

oon. 
Zygosis  —  conjugation,  and  zygote  =  the  resulting  body. 
— g^^y  =  production  by — e.g.,  parthenogeny,  sporogeny. 
— genesis  =  production  of- — e.g.,  spermatogenesis. 
— -//aj/i-  =  making  of — e.g.,  gametoplasis. 
— phase  =  p\i2ise  or  cycle — e.g.,  gamophase  (sexual  cycle),  agamophase 

(asexual  cycle),  schistophase,  merophase,  zygophase,  etc. 
— cyte  =  di  cell  destined  to  produce — e.g.,  gametocyte. 
— phore  =  z.    body    actually    producing — e.g.,    sporophore   (sporulating 

body),  spermatophore  (flagellate  body). 
— cyst^z.  capsule  containing — e.g.,  oocyst,  clastocyst, 

621 


622  NOTES  ON  THE  MALARIA-BEARING  ANOPHELINES   [Sect. 

— id=3i  body  connected  with,  or  belonging  to,  the  phase  of — e.g.,  merid, 
sporid,  gametid.  Also  haematid  (red  corpuscle),  leukid  (white 
corpuscle),  micrid  (blood  plate),  etc. 

Descriptions  should,  I  think,  commence  with  the  definite  starting- 
point  of  the  zygote.  Thus  I  should  describe  the  general  cytogenesis 
(or  biogenesis)  of  Plasmodium  briefly  as  follows  : — 

Zygosis  occurs  in  the  stomach  of  the  mosquito.  The  zygote  pene- 
trates into  the  stomach  wall ;  and  after  a  short  schistophase  produces 
about  eight  to  twelve  protoclasts  which,  continuing  schistogenesis, 
produce  a  large  number  of  deuteroclasts.  These,  escaping  from  the 
cyst,  become  protospores ;  which  pass  by  route  of  the  insect's  salivary 
glands  into  the  vertebrate  blood,  where  each  penetrates  a  haematid. 
Here  the  sporid,  after  another  schistophase,  produces  six  to  thirty 
deuterospores,  the  sporophase  being  thus  continued  indefinitely.  The 
gamophase  commences  (by  stages  not  yet  clearly  seen)  in  the  vertebrate 
blood.  The  oocyst  has  one  oon,  and  the  spermatocyte,  say,  four  to  six 
sperms ;  but  gametophoresis  and  zygosis  do  not  occur  until  the  blood 
is  ingested  by  another  Culicid.^ 

63.  Notes  on  the  Malaria  -  bearing-  Anophelines.  —  This 
section  ought  to  have  been  placed  in  Chapter  III,  but  has  been 
relegated  to  the  Addenda  for  the  following  reasons.  Many  works  on 
malaria  and  on  mosquitos  give  lists  of  the  malaria-bearing  Anophelines, 
but  mostly  without  exact  references  to  the  literature  in  which  the 
incriminating  evidence  was  published.  Hence  early  in  1910  I  directed 
Mr  W.  R.  Drawz,  our  Malaria  Bibliographer  (Tropical  Diseases' 
Research  Fund),  to  collect  all  the  data  which  he  could  find ;  but  the 
work  could  not  be  completed  in  time  for  the  earlier  chapters  of  this 
book ;  and  he  reports  that  even  now,  after  several  months'  close  search, 
some  references  have  probably  been  overlooked.  I  am  also  much 
indebted  to  Mr  R.  Newstead  and  Dr  J.  W.  W.  Stephens,  of  the 
Liverpool  School  of  Tropical  Medicine,  for  their  valuable  assistance. 

(i)  So  far  as  we  can  find,  the  following  is  a  complete  list  of  the 
Anophelines  which  have  been  mentioned  in  various  books  and  papers 
as  being  capable  of  carrying  malaria  : — 

(Note. — Only  synonyms  in  small  type.) 

A?topheles  albimatia,  Theobald  (1901),  vide 

Cellia  albimana,  (Wiedemann)  (1821). 
Anopheles  albimana,  Wied.,  xnde 

Cellia  albimatia,  (Wiedemann)  (1821). 

^  I  am  indebted  to  Professors  Myres  and  Postgate,  University  of  Liverpool,  for 
advice  regarding  the  Greek  roots. 


63]  ADDENDA  623 

Anopheles  albimanus,  R.  D.,  vide 

Cellia  argyrotarsis^  (Robin-Desv.)  (1827). 
Anopheles  albitarsis,  Arribalzagia  (1901),  vide 

Cellia  argyrotarsis^  (Robin-Desv.)  (1827). 

Anopheles  algeriensis,  Theobald  (1903). 
Anopheles  annulipes,  Walker  (1850),  vide 

Nyssorhynchus  annulipes,  (Walker)  (1850). 

Aitopheles  arabiensis,  Patton  (1905). 

Anopheles  barbirostris.  Van  der  Wulp  (1884),  vide 
Myzorhynchiis  barbirostris,  {yzxi  der  Wulp). 

Anopheles  bifurcatus,  (Linn.)  (1758). 

Anopheles  bifurcatus,  Meigen  (1804),  vide 

Anopheles  maculipennis,  Meigen  (18 18). 
Anopheles  chaudoyei.  Billet  {is  not  a  spec),  vide 

Pyretophorus  chaudoyei,  Theobald  (1903). 
Anopheles  claviger,  Fabr.  (1805),  vide 

Anopheles  maculipennis,  Meigen  (18 18). 
Anopheles  claviger,  Meigen  (1804),  vide 

Anopheles  bifurcatus,  (Linn.)  (1758). 

Anopheles  cohaesus,  Donne. 

Anopheles  costalis,  Loew  (1866),  vide 

Pyretophorus  costalis,  (Loew)  (1866). 

Anopheles  crucians,  Wiedemann  (1828). 

Anopheles  culicifacies,  Giles  (1901),  vide 

Myzomyia  culicifacies,  (Giles)  ($  non  ^)  (1901). 

Anopheles  farauti,  Laveran  (1902).  (Doubtful  species.) 

Anopheles  forniosaensis,  Tsuzuki  (1902)  (?  Genus  Anopheles). 
Anopheles  fuliginosus,  Giles  (1900),  vide 

Nyssorhynchus  fuliginosus,  (Giles)  (1900). 
Anopheles  funesta,  Giles  (1900),  vide 

Myzomyia  funesta,  (Giles)  (1900). 
Anopheles  funesta  var.  subuvibrosa,  Theobald  (1900),  vide 

Myzomyia  funesta,  (Giles)  (1900). 
Anopheles  fujiesta  var.  umbrosa,  Theobald  (1900),  vide 

Myzotnyia  funesta,  (Giles)  (1900). 
Anopheles  gambiae,  Giles  (1902),  vide 

Pyretophorus  costalis,  (Loew)  (1866). 
Anopheles  grabhantii,  Theobald  (1901),  vide 

Cycloleppteron  grabhamii,  (Theobald)  (1903). 


624   NOTES  ON  THE  MALARIA-BEARING  ANOPHELINES  [Sect. 

Anopheles  gracilis,  Donitz  (1902),  vide 

Pyretophorus  cos  talis,  (Loew)  (1866). 
Anopheles  jamesii.  Listen  (non  Theobald)  (1901),  vide 

Nyssorhynchus  fuliginosus,  (Giles)  (1900). 
Anopheles  jesoensis,  Tsuzuki  (1902),  vide 

Myzorhynchus  sinensis,  (Wiedemann)  (1828). 
Anopheles  kawari,  James-Liston  (1901),  vide 

Nyssorhynchus  kawari,  James-Theobald  (1901). 
Ajtopheles  kochii,  Donitz  (1901),  vide 

Cellia  kochii,  (Donitz)  (1901). 
Anopheles  kumasii,  Chalmers  (1900),  vide 

Mysojuyia  funesta,  (Giles)  (1900). 
Anopheles  leucopus,  Donitz  (1901),  vide 

Nyssorhynchus  fuliginosus,  (Giles)  (1900). 
Anopheles  listoni,  Giles  (1901)  (?  ^  only),  vide 

Myzoinyia  ctdicifacies,  (Giles)  (  $  non  (J)  (1901). 
Anopheles  listoni,  Liston,  vide 

Myzomyia  listoni,  Liston  (non  Giles)  (1901). 
Anopheles  lutzii,  Theobald  (1901),  vide 

Myzomyia  lutzii,  Theobald  (1905). 
Anopheles  maciilipalpis,  Giles  (1902),  vide 

Nyssorhynchus  inacidipalpis  (Giles)  (1902). 

Anopheles  maculipennis,  Meigen  (18 18). 

Anopheles  martini,  Laveran  (1902). 

Anopheles  metaboles,  (Theobald)  (1902),  vide 

Nyssorhynchus  stephensi,  (Liston)  (1901). 
Anopheles  musivus,  Skuse  (1888),  vide 

Nyssorhynchus  annulipes,  (Walker)  (1850). 
Anopheles paludis,  Theobald,  vide 

Myzorhynchics  paludis,  (Theobald)  (1900). 
Anopheles  pharoefisis,  Theobald  (1901),  vide 

Cellia  pharoetisis,  (Theobald)  (1901). 
?  Anopheles picius,  M'Donald,  vide 

Myzomyia  hispaniola,  Theobald  (1903). 

Anopheles pseiidopunctipennis,  Theobald  (1901). 
Anopheles punctipennis,  Say  (1823). 

Anopheles pursati,  Laveran  (1902). 

Anopheles  quadrimaculatus,  Say  (1824),  vide 

Anopheles  jnaculipennis,  Meigen  (18 18). 
Anopheles  rossii,  Giles  (1899),  vide 

Myzomyia  rossii,  (Giles)  (1899). 


63]  ADDENDA  625 

Anopheles  sinensis^  Wiedemann  (1828),  vide 

Myzorhytichus  sinensis,  (Wiedemann)  (1828). 

Anopheles  stephensi.  Listen,  vide 

Nyssorhynchus  siephensi,  (Listen)  (1901). 

?  Anopheles  superpictus,  Grassi,  vide 

Pyretophorus  superpictus,  (Grassi)  (1900). 

Anopheles  tarsimaculata,  Goeldi  (1905)  (not  Anopheles). 
Anopheles  theobaldi,  Giles,  vide 

Nyssorhynchus  theobaldi,  (Giles)  (1901). 

Anopheles  treacheri,  (?  Daniels  1909). 

Anopheles  trifurcatus,  Fabricius  (?  date),  vide 

Anopheles  bifurcatus,  (Linn.)  (1758). 
Anopheles  turkhudi,  Listen,  vide 

Myzomyia  turkhudi,  (Listen)  (1901), 
Anopheles  vagus,  Donitz  (1902),  vide 

Myzomyia  rossii,  (Giles)  (1899). 
Anopheles  villosus,  Reb.-Des.  (1827),  vide 

Anopheles  bifurcatus,  (Linn.)  (1758). 

Anopheles  vincenti,  Laveran  (1901). 

Anopheles  walkeri,  Theebald  (1901),  vide 
Anopheles  bifurcatus,  (Linn.)  (1758). 

Arribalzagia  maculipes,  Theobald  (1903). 

Cellia  albimana,  (Wiedemann)  (1821). 

Cellia  albipes,  Theebald  (1903),  vide 

Cellia  albimana,  (Wiedemann)  (1821). 

Cellia  argyrotarsis,  (Rob.-Des.)  (1827). 

Cellia  kochii,  Donitz  (1901). 

Cellia  pharoensis  (Theobald)  (1901). 

Culex  bifurcatus,  Meigen  (1804),  vide 

Anopheles  niaculipennis,  Meigen  (18 18). 
Culex  hyemalis.  Fitch,  vide 

Anopheles punctipennis,  Say  (1823). 

Cycloleppteron  grabhamii,  Theobald  (1903). 

Cycloleppteron  mediopunctalus,  (Lutz  M.S.),  Theobald. 

Myzomyia  christophersi,  Theobald  (1902),  vide 

Myzomyia  listoni,  Listen  (non  Giles)  (1901). 

2  R 


626   NOTES  ON  THE  MALARIA-BEARING  ANOPHELINES  [Sect. 

Myzomyia  culicifacies,  (Giles)  (  %  non  ^  )  (1901). 
Myzomyiafluviatilis,  Christophers  M.S.  (1901),  vide 
Myzomyia  listoni,  Liston  (non  Giles)  (1901). 

Myzomyia  funesta,  (Giles)  (1900). 

Myzomyia  kispaniola,  Theobald  (1903). 
Myzomyia  indica,  Theobald  (1901),  vide 

Myzomyia  culicifacies,  (Giles)  (  $  non  $)  (1901). 

Myzomyia  listoni,  Liston  (non  Giles)  (1901). 

Myzomyia  ludlowi,  Theobald  (1903). 

Myzomyia  lutzii,  Theobald  (1905). 

Myzomyia  nili,  Theobald  (1904). 

Myzomyia  rossii,  (Giles)  (1899). 

Myzomyia  turkhudi,  (Liston)  (1901). 

Myzorhynchus  barbirostris,  (Van  der  Wulp). 

Myzorhynchus  coustani,  (Laveran)  (1902), 

Myzorhynchus  mauritianus,  (Grandpre)  (1900). 

Myzorhynchus  paludis,  (Theobald)  (1900). 

Myzorhynchus  paludis  var.  similis,  Theobald  (1901),  vide 

Myzorhynchus  mauritianus,  (Grandpre)  (1900). 
Myzorhynchus  pictus,  Ficalbi  (1899),  vide 

Myzorhynchus pseudopictus,  (Grassi)  (1899). 

Myzorhynchus  pseudopictus,  (Grassi)  (1899). 

Myzorhynchus  sinensis,  (Wiedemann)  (1828). 
Myzorhynchus  tenebrosus,  Donitz  (1902),  vide 

Myzorhynchus  mauritianus,  (Grandpre)  (1900). 

Myzorhynchus  umbrosus,  Theobald  (1903), 

Myzorhynchus  ziemanni.  Von  Griinberg  (1902). 

Nyssorhynchus  annulipes,  (Walker)  (1850). 

Nyssorhynchus  fuliginosus,  (Giles)  (1900). 

Nyssorhynchus  kawari,  James-Theobald  (1901). 


63]  ADDENDA  627 

Nyssorhynchus  maadipalpis,  (Giles)  (1902). 

Nyssorhynchus  maadipalpis  var.  indiensis,  Theobald  (1903),  vide 
Nyssorhynchus  maculipalpis,  (Giles)  (1902). 

Nyssorhynchus  maculatus,  (Theobald)  (1900). 

Nyssorhynchus  stephensi,  (Listen)  (1901). 

Nyssorhynchus  theobaldi,  (Giles)  (1901). 

Nyssorhynchus  willmori,  James  (Theobald)  (1904). 

Pyretophorus  ardensis,  Theobald  (1905). 

Pyretophorus  chaudoyei,  Theobald  (1903). 

Pyretophorus  costalis,  (Loew)  (1866). 

Pyretophorus  costalis  var.  melas^  Theobald  (1903),  vide 
Pyretophorus  costalis^  (Loew)  (1866). 

Pyretophorus  Jeyporensis,  Theobald  (1903). 

Pyretophorus  myzomyifacies,  Theobald  (1907). 

Pyretophorus  sergenti,  Theobald  (1907). 

Pyretophorus  superpictus,  (Grassi)  (1900). 

Stethomyia  fragilis^  (Theobald)  vide 

Anopheles  treachtri^  (?  Daniels)  (1909). 

Stethoinyia  nimba,  Theobald. 

(2)  I  now  add  some  notes  on  the  species  regarding  which  we  have 
succeeded  in  finding  some  incriminating  evidence.  That  evidence 
is  of  three  degrees  of  value : — {a)  experimental  proof  that  certain 
individuals  of  a  species  are  capable  of  developing  all  the  stages 
of  any  or  all  the  species  of  the  human  PIas?nodia,  or  of  causing 
infection  in  man,  or  of  both ;  (b)  proof  that  a  species  may  contain 
some  of  the  stages  of  the  parasites  (zygotes) ;  and  {c)  apparent  correla- 
tion between  the  numbers  of  a  species  and  the  local  prevalence  of 
malaria.  Here  (b)  is  not  conclusive  because,  though  the  zygotes  may 
develop  to  a  certain  degree  in  an  insect,  it  does  not  follow  that  they 
come  to  maturity ;  and  {c)  is  not  worth  much  because,  as  we  showed 
in  the  case  of  Myzorhynchus  mauritianus,  a  species  may  abound  in  a 
malarious  locality,  although  the  disease  is  really  being  spread  by  quite 
another  one.     Lastly,  even  {a)  proves  only  that  the  variety  concerned 


628   NOTES  ON  THE  MALARIA-BEARING  ANOPHELINES  [Sect. 

in  the  experiments  is  culpable,  because,  for  instance,  we  failed  in 
infecting  English  A.  maculipennts,  which  certainly  carry  in  most  other 
places.  The  reader  should  also  note  that  the  breeding-waters  selected 
by  larvae  in  some  places  need  not  necessarily  be  the  same  as  those 
selected  by  the  same  larvae  elsewhere. 

Anopheles  algeriensis. — Ed.  and  Et.  Sergent  state  that  they  found 
protospores  in  the  salivary  glands  of  the  two  individuals  examined  by 
them  [1905].  They  also  state  that  a  violent  epidemic  of  malaria 
occurred  in  the  villages  of  Thiers  in  Algeria,  where  it  was  not 
possible  to  find  any  other  Anopheline  except  this  one.  Occurs  in 
Algeria,  and  the  Sergents  say  that  it  haunts  les  collines  saheliennes^ 
and  the  plains  of  the  littoral. 

Anopheles  arabiensis. — Apparently  incriminated  by  W.  S.  Patton 
[1905].  Literature  not  available.  Protospores  found  in  it.  Distribu- 
tion :  Arabia  and  Aden.  See  Stephens  and  Christophers  [1907, 
p.   156]. 

Anopheles  bifurcatus. — There  are  two  species  of  Anophelines  under 
the  name  of  claviger,  A.  maculipennts  Fabr.  and  A.  bifurcatus  Linn. 
Both  appear  to  have  been  incriminated  by  the  Italians  by  cultivation  of 
the  parasites  in  all  their  stages,  and  also  by  inoculation  of  healthy 
persons  (see  section  17,  cases  2,  3,  4) ;  but  it  is  not  always  clear  which 
species  is  referred  to.  We  gather  that  A.  maculipennis  is  the  one 
concerned  in  the  experimental  inoculations,  and  generally  in  the  cultiva- 
tions. But  Bignami  and  Bastianelli  also  incriminated  bifurcatus  by 
cultivation.  Grassi  says  [1901]  that  he  found  it  much  more  difficult 
to  work  with  bifurcatus  than  with  maculipennis,  owing  to  the  small  size 
of  the  former,  but  found  zygotes  in  thirteen  out  of  sixteen  insects,  and 
adds  (page  121,  German  edition)  that  parasites  were  found  in  bifurcatus 
and  maculipennis  in  the  Maccarese  district.  Jansc6  also  [1904,  1905 
and  1908]  gives  experiments  with  A.  claviger  without  stating  which 
claviger  he  referred  to ;  but  we  gather  that  he  was  referring  to  maculi- 
pennis.    Probably  bifurcatus  can  be  safely  claimed  as  a  carrier. 

It  is  generally  distributed  over  Europe  and  North  America.  In 
England  it  is  certainly  the  commonest  of  the  three  Anophelines,  the 
other  species  being  maculipettnis  and  nigripes.  Grassi  states  that  it 
occurs  in  forests  and  breeds  in  small  collections  of  fresh  water  such  as 
wells  and  in  rot  holes  in  trees ;  that  it  occurs  seldom  in  houses  and 
stables,  and  that  when  one  is  bitten  in  forests  it  is  generally  by  this 
species.     It  bites  more  quickly  than  A.  claviger,  and  in  the  daytime, 


63]  ADDENDA  629 

and  enters  habitations  at  night.  Newstead  says  that  it  is  the 
commonest  Anopheline  in  the  New  Forest  in  England,  where  the 
larvae  occur  in  large  numbers  in  the  shallow  pools  and  in  the  cattle 
footprints.  In  the  marshes  of  Cheshire  it  is  also  abundant,  occurring 
chiefly  in  shallow,  terrestrial  waters,  sometimes  in  company  with  the 
larvae  of  Culex. 

Anopheles  formosaensis. — The  generic  position  of  this  species  has 
not  yet  been  definitely  fixed.  Incriminated  by  J.  Tsuzuki  [1902],  who 
followed  completely  the  development  of  the  malignant  parasites  in  it, 
but  did  not  inoculate  man  with  it.  Occurs  in  the  whole  island  of 
Formosa.  Tsuzuki  apparently  distinguishes  two  varieties,  one  of  which 
is  common  in  the  north  and  the  other  in  the  south  of  Formosa. 

Anopheles  maculipennis. — Incriminated  by  the  Italians,  see  under 
A.  bifurcatus  ;  also  by  A.  Van  de  Scheer  and  Van  Berlekom  [1900J, 
by  Schaudinn  [1903],  by  Hirschberg  [1904],  Husson  [1907],  and  by 
Jansco  [1904,  1905,  1908],  and  others.  The  proof  is  by  complete 
cultivation  of  the  parasites,  and  also  by  inoculation  of  man  by  the 
Italians  and  by  Jansc6.  Common  and  generally  distributed  through- 
out Europe,  including  Russia  and  Scandinavia.  It  appears  also  to 
be  generally  distributed  in  the  United  States  of  America,  and  to  be 
common  in  many  parts  of  Canada.  It  is  chiefly  a  domestic  insect, 
found  in  houses,  sheds,  stables,  and  hen  coops,  etc.  This  habitat  also 
obtains  to  a  very  large  extent  in  Great  Britain.  The  larvae  occur 
chiefly  in  open  terrestrial  waters  in  marsh  lands,  in  forests  and  boggy 
places.  Theobald  states  that  in  Britain  the  food  of  both  sexes  is 
entirely  vegetable.  Ficalbi,  on  the  other  hand,  says  it  is  very  trouble- 
some to  man  in  Italy. 

A.  psetidopunctipennis. — Incriminated  by  S.  T.  Darling  [1910],  who 
found  zygotes  in  four  out  of  thirty-one  insects  fed  on  cases  of  the 
malignant  parasites,  and  also  protospores  in  the  glands  of  one  insect. 
He  thinks  that  it  is  only  slightly  concerned  in  the  transmission  of 
malarial  fever  in  the  Canal  Zone.  Occurs  in  Panama,  Grenada  and 
New  Mexico.  Darling  says  that  it  is  one  of  the  two  commonest 
species  in  the  Canal  Zone,  and  breeds  in  most  terrestrial  waters. 

A.  tarsimaculata. — Incriminated  by  S.  T.  Darling  [19 10],  who 
found  zygotes  in  three  out  of  five  insects.  Occurs  in  Panama  and 
South  America.  It  is  doubtful  if  this  species  is  referable  to  the  genus 
Anopheles. 


630   NOTES  ON  THE  MALARIA-BEARING  ANOPHELINES  [Sect. 

Cellia  albimana. — Incriminated  by  S.  T.  Darling  [19 10],  who  found 
zygotes  in  thirty-six  out  of  fifty  insects  and  protoclasts  and  protospores 
in  three.  Occurs  in  Panama,  Brazil,  British  Guiana  and  in  the  West 
Indies.  Theobald  (vol.  iii.  p.  iii)  states  that  Dr  St  George  Gray 
says  that  this  Anopheline  will  bite  at  any  time  of  the  day  or  night ; 
that  the  breeding-grounds  are  extremely  varied,  such  as  collections  of 
water,  especially  full  of  reeds ;  and  records  also  that  he  has  found 
larvae  in  brackish  water  in  a  lagoon  shut  off  from  the  sea.  He  states, 
however,  that  he  has  never  found  the  larvae  in  water  barrels  or  similar 
receptacles  in  towns.  Darling  [1909,  19 10]  says  that  this  and  pseudo- 
punctipennts  are  the  commonest  mosquitos  in  the  Panama  Canal  Zone, 
and  breed  in  almost  any  terrestrial  water.  It  carries  both  malignant 
and  tertian  malaria.  Theobald,  in  his  "  Mosquitos  of  Jamaica,"  also 
mentions  rivers  and  large  swamps  and  irrigation  water,  etc.,  as  breeding- 
places. 

Cellia  argyrotarsis. — S.  T.  Darling  [19 10]  says  that  a  zygote  was 
found  in  one  individual  at  Panama.  Occurs  in  South  America,  the 
West  Indies,  Panama,  but  appears  not  to  be  an  important  carrier. 
From  the  records  we  gather  that  this  is  a  less  common  species  than 
C.  albimana,  to  which  it  is  very  similar  (possibly  only  a  variety). 

Cellia  pharoensis. — Newstead,  Dutton  and  Todd  [1907-1908]  say 
that  "  malaria  parasites  were  seen  to  develop  in  this  mosquito  at 
Boma."  The  insect  was  common  at  Ismailia,  and  has  been  reduced 
simultaneously  with  malaria  by  operations  since  1902  (section  53). 
Pressat  [1905]  considers  it  to  be  malaria-bearing,  but  gives  no  evidence. 
Occurs  in  East,  West,  Central  and  Northern  Africa.  It  is  recorded 
also  from  Palestine.  Theobald  (vol.  i.,  1901)  says  that  this  mosquito 
occurs  during  the  month  of  April  in  Mashonaland  and  during  January 
in  Egypt.  I  found  the  larvae  in  small  swamps  of  almost  fresh  water 
caused  by  seepage  from  the  fresh-water  canal  at  Ismailia,  also  in  an 
ornamental  fountain  and  in  water-cress  beds.  Not  seen  in  sewage 
cisterns.  Willcocks  say  that  it  is  a  domestic  mosquito,  both  in  the 
larval  and  adult  stages.  The  adults  enter  houses  in  order  to  obtain 
blood.  In  the  open  the  females  bite  most  viciously  at  sunset.  The 
water  in  which  the  larvae  live  may  be  brackish.  Larvae,  in  various 
stages  of  development,  placed  in  water  containing  i'78%  common  salt, 
die  in  less  than  twenty-four  hours,  but  in  water  containing  1%  common 
salt  they  live  from  two  to  three  days,  but  become  sluggish  in  their 
movements  and  appear  to  feed  very  little  or  not  at  all. 


63]  ADDENDA  631 

Myzomyin  cuUcifacies. — Incriminated  by  Stephens  and  Christophers 
[25th  April  1902].  Experimentally  it  carries  quartan  as  far  as  the 
protospores,  and  the  other  two  species  as  far  as  the  zygotes.  In 
nature  frequently  found  to  be  infected  in  4-6%  at  Mian  Mir,  and  in 
8'6%  at  Ennur,  near  Madras.  Widely  spread  in  India,  where  it  is  one 
of  the  principal  carriers.  Breeds  in  pools  in  sandy  river-beds,  sluggish 
irrigation  channels,  ditches,  muddy  tricklets,  edges  of  rivers,  etc. 

Myzomyia  fimesta.- — Proved  by  Ross,  Annett  and  Austen  [1900] 
to  carry  quartan  (one  out  of  five  insects)  and  mild  tertian  (one  insect) 
in  West  Africa.  Further  confirmed  by  Daniels  [1900,  p.  41]  for 
malignant.  Stephens  and  Christophers  [1901]  found  what  appeared 
to  be  this  Anopheline  in  the  Duars,  in  India,  but  Theobald  subse- 
quently did  not  admit  the  identity.  Also  observed  by  Button  and 
Todd,  who  report  that  malaria  was  seen  to  develop  in  it  at  Lusambo 
[1907].  Occurs  in  Central,  Western  and  Southern  Africa,  Sudan  and 
the  Philippine  Islands.  Breeds  in  clear  water  in  small  springs  and 
edges  of  streams  and  rivers.  Daniels  says  it  cannot  thrive  in  stagnant 
waters,  and  that  it  may  be  found  in  marshes,  but  only  where  the 
water  is  kept  fresh  by  springs  during  heavy  rainfall.  Stephens  and 
Christophers  say  that  it  breeds  in  running  waters,  such  as  sluggish 
irrigation  channels,  ditches,  etc.  It  frequents  houses  and  does  not 
leave  them  in  the  daytime.  It  feeds  preferably  at  night,  especially 
in  the  early  hours  of  the  evening,  but  also  at  other  times,  even  in 
dayhght,  both  when  free  and  in  captivity. 

Myzomyia  hispaniola. — Incriminated  by  Sergent  brothers  [1905], 
who  dissected  fourteen  in  1904  without  result,  but  in  1905  found 
protospores  in  one  of  three  dissected.  Occurs  in  Spain,  Teneriffe, 
Algeria.  The  Sergents  say  that  it  abounds  above  all  in  valleys  of 
hilly,  broken  regions,  but  that  it  is  found  at  a  distance  of  some 
kilometres  in  the  plains  in  the  debouche  of  these  valleys,  and  add 
that  this  Anopheline  is  like  algeriensis  but  is  little  domestic.  It 
frequents  houses  only  during  the  night,  and  does  not  remain  after 
having  bitten  its  victim. 

Myzomyia  listoni. — Incriminated  by  Stephens  and  Christophers. 
In  this  species  protospores  were  readily  found  in  the  Bengal  Duars, 
but  only  in  nature.  Also  by  Kinoshita  [1906],  who  says  it  can  be 
infected  from  50  to  98%  in  Formosa.  Occurs  in  India,  Japan, 
Federated    Malay   States,      Inhabits   running   waters,   swiftly  -  flowing 


632    NOTES  ON  THE  MALARIA-BEARING  ANOPHELINES  [Sect- 

streams,    sluggish   irrigation    channels,    ditches,    muddy   tricklets   and 
edges  of  rivers. 

Myzomyia  lutzii. — Lutz  [1903]  says  that  he  is  convinced  that  this 
mosquito  carries  malaria,  but  gives  no  further  evidence.  Oswaldo 
Cruz  (section  47)  suspects  it.  Occurs  in  Brazil,  British  Guiana.  Lutz 
who  paid  considerable  attention  to  the  bionomics  of  this  mosquito, 
states  that  it  is  found  widely  distributed  in  various  places  along  the 
chain  of  mountains  in  the  region  of  San  Paolo  and  Santos.  It  breeds 
in  Bromilaceous  plants. 

Myzomyia  rossii. — I  failed  in  infecting  this  species  in  Calcutta  in 
1898-1899.  Stephens  and  Christophers  [1902]  obtained  experimentally 
quartan  and  malignant  zygotes  in  a  few  individuals.  Never  found 
them  infected  in  nature.  They  add  that  zygotes  were  found  in  nature 
by  Captain  James,  but  sporozoits  never  in  nearly  1,000  dissected. 
W.  T.  de  Vogel  [1909]  found  zygotes  in  two  insects  bred  from  larvae 
grown  in  salt  water  (i'3%),  but  not  in  those  bred  in  fresh  water. 
C.  A.  Bentley  also  finds  them  in  sea  water;  and  failed  to  discover 
the  parasites  in  425  dissected.  Occurs  in  India,  Ceylon,  Malay  States, 
China,  East  Indies,  Philippine  Islands,  and  Java.  Breeds  in  foul 
puddles  near  habitations,  clean  clear  water  puddles  without  much 
algae,  and  often  turbid  with  suspended  matter,  boats  and  puddles 
near  houses,  shallow  muddy  rivers,  rice  fields  and  cultivation  of  all 
kinds.  Theobald  states  that  Mr  E.  E.  Green  {Tropical  Agriculture, 
vol.  xxvii.  p.  84,  1906)  considers  that  it  is  a  malaria  carrier  in  parts 
of  Ceylon.  He  found  the  larvae  breeding  in  a  brackish  lake  at 
Batticaloa,  and  also  in  the  cocoanut  estates,  in  the  small  water  holes 
used  for  watering  young  plants,  and  in  chatties  sunk  at  the  roots  of 
plants.  I  have  often  thought  that  the  comparative  healthiness  of 
India  may  be  due  to  the  fact  that  this  species  ousts  more  dangerous 
ones.     Vogel's  suggestion  is  interesting.^ 

Myzomyia  turkhudi. — Incriminated  by  Stephens  and  Christophers 
[1902].  Found  to  carry,  experimentally,  malignant  tertian  zygotes. 
Occurs  in  India ;  and  found  in  large  pools  in  quarries,  stony  and 
shallow  running  waters. 

Myzorhynchus  barbirostris. — Proved  by  Stephens  and  Christophers 
[1902]  to  develop  malignant  tertian  experimentally.  Their  first  experi- 
ments had  been  negative.     Occurs  in  India,  Malay  Peninsula.     Stated 

^  See  also  section  65  (8). 


63l  ADDENDA  633 

to  have  been  found  at  Old  Calabar  (?).  Breeds  in  running  waters 
with  much  weed  and  algae,  swamps,  and  deep  water  with  much  aquatic 
vegetation. 

Myzorhynchus  sinensis. — Tsuzuki  [1902]  proved  that  the  parasites 
develop  in  all  stages  in  this  mosquito  and  that  it  causes  infection 
in  a  healthy  man.  Also  that  quartan  parasites  develop  in  many  of 
these  mosquitos ;  but  he  did  not  infect  man  with  this  species  of 
parasite.  Kinoschita  cultivated  mild  tertian  parasites  in  seven  out  of 
sixteen  mosquitos,  but  quartan  only  at  low  temperatures,  and  malignant 
parasites  not  at  all.  Occurs  in  Formosa,  Japan,  China,  Federated 
Malay  States.     Habits  not  described. 

Myzorhynchus  umbrosus. — Incriminated  by  Malcolm  Watson.  Ex- 
periments not  mentioned,  but  certainly  a  carrier.  Occurs  in  the 
Federated  Malay  States.  Breeds  principally  in  the  flat  country,  but 
not  in  flowing  water.  Abounds  in  thick  jungle  which  it  will  not 
willingly  leave,  so  that  removal  of  jungle  round  plantations  reduces 
malaria  (section  57). 

Nyssorhynchus  annulipes. — Kinoshita  [1906]  developed  malignant, 
only  at  high  temperature  without  oscillations,  in  three  out  of  five 
mosquitos.  Occurs  in  South  West  Queensland,  Australia,  Formosa. 
Donitz  says  it  occurs  in  the  Bismarck  Islands.  Breeds  both  in  fresh 
and  in  salt  water  (1,040  sp.  gr.),  and  will  live  for  a  month  on  dates. 

Myzorhynchus  fuliginosus.- — Incriminated  by  Stephens  and  Christo- 
phers [1902]  and  Adie  [1903].  Stephens  and  Christophers  say  that 
it  occurred  in  Mian  Mir  in  small  numbers,  and  think  that  it  is  not 
an  active  agent.  They  were  able  to  infect  it  experimentally  for 
malignant  tertian  (zygotes),  in  one  case  sixty-six  medium  and  ten  small 
zygotes.  It  developed  also  quartan  up  to  zygotes,  experimentally. 
Occurs  in  India,  Federated  Malay  States.  Breeds  in  puddles  and 
pools  with  much  algae,  common  in  stream  beds,  water  trickling  over 
rocks  and  lakes  with  weedy  margins.  Giles  and  Liston  say  that  as 
a  rule  this  species  prefers  open  water  and  sunlight. 

Nyssorhynchus  niaculipalpis.  —  Stephens  and  Christophers  found 
zygotes  experimentally  in  this  mosquito,  which  they  called  N.  jamesii. 
Occurs  in  India,  Mauritius,  Mashonaland.  Scarce  in  Mauritius. 
Breeding  in  marshes  on  sea  coast,  and  at  1,400  feet  above  sea. 

Nyssorhynchus     stephensi.  —  Stephens     and     Christophers    [1902] 


634  NOTES  ON  THE  MALARIA-BEARING  ANOPHELINES  [Sect. 

developed  zygotes  of  malignant  tertian  in  it,  experimentally.  W.  G. 
Listen  [1908]  at  Bombay  found  25%  infected  with  malaria. 
C.  A.  Bentley,  in  the  same  city  [19 10],  found  zygotes  in  30  and 
protospores  in  8  out  of  404  dissections.  Occurs  in  many  parts  of 
India.  Breeds  not  only  in  open,  clean  terrestrial  waters,  but  in  deep 
wells,  iron  cisterns,  filter  beds,  garden  tanks,  and  even  small  vessels 
(section  59). 

Nyssorhynchus  theobaldia.  —  Stephens  and  Christophers  [1902] 
developed  malignant  tertian  and  quartan  to  zygotes,  experimentally. 
Occurs  in  India  and  Aden  Hinterland.  Breeds  in  running,  stony  and 
shallow  water  with  much  weed  and  algae. 

Nyssorhynchus  willmori.  —  Incriminated  by  Malcolm  Watson 
(section  57).  Details  of  experiments  not  given,  but  the  insect  appears 
to  be  certainly  a  carrier  in  the  hilly  land  in  the  Federated  Malay 
States.  Also  Daniels  [1909].  Occurs  in  Federated  Malay  States, 
Kashmir,  Ceylon.  Breeds  in  rapidly  running  streams,  and  cannot  be 
reduced  by  open  drainage.  The  larvae  were  found  in  the  clear  puddles 
formed  by  a  spring  at  a  height  of  4,800  feet  in  Kashmir  (Theobald, 
vol.  iii.  p.  102). 

Pyretophorus  chaudoyei. — Billet  states  that  this  mosquito  occurs 
exclusively  in  places  where  there  is  much  malaria  in  the  Saharian  Oases 
in  Algeria.  He  had  no  opportunity  of  finding  zygotes  in  the  insects, 
but  is  sure  that  it  is  a  carrier.  Theobald  (vol.  iii.  p.  70)  says  that 
protospores  have  been  found  in  it.  Occurs  in  Algeria,  Touggourt  in 
Algeria,  and  southern  posts  in  Sahara.  Breeds  in  water  containing  a 
higher  percentage  of  salt  than  normal  sea  water.  Larvae  are  found  in 
little  isolated  pools  or  ponds,  which  under  the  influence  of  active  solar 
radiation  greatly  increase  in  the  percentage  of  salt,  giving  at  the  end 
of  summer  a  percentage  of  40  grammes  per  litre.  (Foley  and 
Yvermault,  Bull.  Soc.  Path.  Exot.,  1908,  i.  iii.  pp.  172-173.) 

Pyretophorus  costalis.  —  Incriminated  by  Ross,  Annett,  Austen 
[1900]  to  carry  all  three  species  in  27  out  of  109  insects.  Also  by 
Stephens  and  Christophers  [1900]  and  by  R.  Ross  in  Mauritius 
[1908].  Common  and  widely  distributed  over  the  African  continent, 
Madagascar,  Reunion  and  Mauritius,  but  not  in  many  neighbouring 
islands  which  are  non-malarious.  Breeds  in  stagnant  terrestrial  waters 
often  without  much  weed.  Appears  to  prefer  the  sea  coast  in  Mauritius, 
but  was  found  in  marshes  up  to  1,700  feet,  where,  though  scanty,  it 
yet  caused  malaria.     Breeds  in  pools  in  dried-up  beds  of  hill  streams, 


63]  ADDENDA  635 

and  in  weedy  margins,  etc.  In  Mauritius  prefers  verandas  to  inner 
rooms,  and  bites  in  the  open,  especially  after  11  p.m.  Takes  shelter 
from  wind,  but  wanders  far  on  windless  nights. 

Pyretophorus  niyzomyiafacies  {?). — Incriminated  by  Ed.  Sergent 
(section  52),  who  says  that  the  protospores  have  been  found  in  it. 
Occurs  in  Algeria,  especially  in  broken,  hilly  valleys. 

Pyretophonis  siiperpictus. — Grassi  seems  to  think  that  it  is  a  malaria 
carrier  [German  translation,  p.  219,  1901],  but  apparently  gives  no 
evidence.  Also  Bignami  and  Bastianelli  think  that  it  is  a  carrier. 
Occurs  in  the  South  of  Italy,  Spain,  Greece,  Algeria,  and  (?)  Africa  and 
India.     Carries  Filaria  immitis. 

This  concludes  the  Anophelines  regarding  which  we  have  been 
able  to  find  any  reliable  experiments,  but  other  species  are  mentioned 
as  being  possible  or  certainly  carriers,  but  without  giving  the  evidence. 
Thus  Oswaldo  Cruz  (section  47)  says  that  Cydoleppteroti  mediopunctaium 
Theobald  and  Lutz,  Cydoleppieron  intermedium  Chagas,  and  Arri- 
balzagia  pseudomaculipes  Chagas,  "  are  undoubtedly  carriers,  as  shown 
experimentally."  C  Daniels,  in  a  letter  to  me  of  the  17th  June,  says 
that  C.  kochii  is  the  constant  in  badly  malarial  suburbs  in  the  Malay 
States,  and  is  absent  or  scanty  in  other  places.  A.  treacheri  [Stethomyia 
fragilis  Theobald)  was  the  only  mosquito  which  he  could  find  in  badly 
malarial  jungles.  He  adds  that  it  was  difficult  to  make  any  experi- 
ments with  these  two  species,  as  they  will  not  live  in  confinement,  and 
says  :  "The  trouble  with  these,  as  with  several  other  mosquitos,  is  that 
whilst  you  cannot  absolutely  include  them  because  there  is  no  positive 
proof  (experimentally),  you  cannot  exclude  them  because  there  is 
no  negative  proof  (experimentally),  and  the  circumstantial  possible 
evidence  is  strong."  Laveran  mentions  two  species  which  he  calls 
pursaii  and  martini  as  being  carriers ;  but  the  entomologists  appear 
not  to  accept  them  as  species.  Obviously  much  more  exact  work 
requires  to  be  done  even  on  this  point,  which  is  so  important  for 
public  prevention. 

C.  S.  Banks  [1907]  states  in  a  lengthy  paper  that  he  cultivated 
Plasmodia  in  Myzotnyia  ludlowii  Theobald,  a  Philippine  Anopheline 
which  breeds  in  rivers  and  streams  and  also  in  sea  water,  and  that  he 
inoculated  a  healthy  person  by  its  means ;  but  certain  points  in  his 
description  suggest  doubts  as  to  the  nature  of  the  bodies  which  he 
considered  to  be  malaria  parasites. 


636  EXAMPLES   OF   LEGISLATION  [Sect. 

64.  Examples  of  Legfislation.  —  Notes  on  legislation  have 
already  been  made  in  section  40  (4)  and  59  (i).  The  object  of  such 
legislation  is  to  give  the  Health  Department  power  (a)  to  enter  private 
premises  (including  houses,  yards,  gardens,  lands  and  estates)  in  order 
to  search  for  mosquitos,  flies,  rats  and  other  annoying  or  dangerous 
vermin ;  {b)  to  destroy  such  vermin  when  found ;  and  {c)  to  prevent 
the  breeding  of  them.  Another  object  is  to  compel  owners  or 
occupiers  to  take  reasonable  precautions  against  such  breeding.  But 
at  the  same  time  the  rights  and  properties  of  the  owners  or  occupiers 
have  to  be  duly  guarded.  Most  civilised  malarious  countries  now 
possess  Health  Acts,  more  or  less  based  upon  precedent,  and  these 
contain  clauses  against  "nuisances."  But  the  word  "nuisance"  is 
not  always  defined  so  as  to  include  the  breeding  of  vermin.  In  such 
cases,  then,  it  suffices  merely  to  extend  by  act  the  definition  of  the 
word  —  if  possible,  to  include  all  vermin  as  well  as  mosquitos.  It 
was  my  duty  in  Mauritius  to  consider  the  local  Ordinances  carefully 
for  this  purpose ;  and  I  drafted  the  following  clauses,  which  were 
scrutinised  and  accepted  by  the  Health  Department  and  by  the 
Procureur- General,  and  then  submitted  to  Government.  (The  first 
clause  here  given  was  meant  to  be  inserted  in  the  definition  of 
"nuisance"  contained  in  the  Health  Ordinance  already  in  existence) : — 

"All  collections  of  water,  rubbish,  refuse,  ordure,  or  other  fluid  or 
solid  substances,  and  all  other  conditions  which  permit,  or  facilitate, 
or  are  likely  to  permit  or  facilitate,  the  breeding  or  multiplication  of 
animal  or  vegetable  parasites  of  men  or  domestic  animals,  or  of 
insects  or  other  agents  which  are  known  to  carry  such  parasites,  or 
which  may  otherwise  cause  or  faciHtate  the  infection  of  men  or 
domestic  animals  by  such  parasites. 

"  It  shall  be  lawful  for  any  sanitary  authority,  or  any  person 
deputed  by  him  in  writing,  to  take  immediate  steps  to  destroy  mosquito 
larvae  on  any  premises  where  they  may  be  found,  and  to  take  such 
action  as  may  be  necessary  to  render  any  pools  or  accumulations  of 
water  unfit  to  be  breeding-places  for  mosquitos. 

"When  such  pools  or  accumulations  of  water  lie  on  premises  under 
the  charge  of  a  public  body  or  corporation,  they  shall  not  be  dealt  with 
as  above  provided,  unless  due  warning  has  been  given  in  writing  to 
such  public  body  or  corporation,  and  no  action  has,  within  reasonable 
delay — not  to  be  less  than  twenty-four  hours — been  taken  by  them.  In 
such  cases  the  expenditure  incurred  shall  be  borne  by  such  public  body 
or  corporation. 

"Any  owner  or  occupier  who  shall  object  to  pools  and  collections 
of  water  on  his  premises  being  dealt  with  as  above  provided,  shall 
within  twenty-four  hours  submit  his  reasons  to  the  sanitary  authority, 


64]  ADDENDA  637 

who,  after  enquiry,  shall  order  such  action  to  be  taken  as  he  shall 
consider  necessary  to  meet  the  provisions  of  this  Ordinance.  Should 
the  objections  be  rejected,  the  measures  originally  ordered  shall  be 
carried  out  at  the  expen-^e  of  the  said  owner  or  occupier. 

"  It  shall  not  be  lawful  for  any  owner  or  occupier  to  allow 
mosquitos  to  breed  on  his  premises,  or  to  allow  the  presence  on  such 
premises  of  any  receptacle  in  which  water  is  kept  or  may  collect,  unless 
such  receptacles  are  properly  protected  from  access  of  mosquitos,  or 
unless  the  water  they  may  contain  is  treated  in  such  a  way  as  to 
prevent  the  breeding  therein  of  mosquitos,  nor  shall  such  owner  or 
occupier  allow  on  his  premises  any  conditions  which  may,  in  any  way, 
be  favourable  to  the  breeding  of  mosquitos. 

"  Trees  on  all  premises  shall  be  at  all  times  kept  freely  lopped  to 
the  satisfaction  of  the  sanitary  authority  by  the  owner  or  occupier, 
and  no  trees  shall  be  allowed  to  grow  within  10  feet  from  any  dwelling- 
house.  The  sanitary  authority  may,  in  writing,  direct  the  said  owner 
or  occupier  to  carry  out  the  above  provision  within  a  reasonable  delay, 
not  to  be  less  than  forty-eight  hours,  and,  in  case  of  non-compliance, 
the  trees  shall  be  lopped  or  cut  down  at  the  expense  of  the  owner 
or  occupier.^ 

"  It  shall  be  lawful  for  the  Director  of  the  Health  Department  to 
make  such  regulations  as  may  be  necessary  to  carry  out  the  provisions 
of  this  Ordinance. 

"  It  shall  be  lawful  for  the  Director  of  the  Health  Department,  in 
any  case  when  the  owner  or  occupier  of  any  premises  is  liable  for  the 
expense  of  any  measures  carried  out  on  his  premises,  to  relieve  such 
owner  or  occupier  from  the  said  expense,  if,  after  enquiry,  the  Director 
is  satisfied  that  such  owner  or  occupier  is  not  in  a  position  to  incur 
such  expense.  In  such  cases  the  expenditure  shall  be  borne  by 
Government." 

Clauses  of  penalties  follow. 

Sir  Rubert  Boyce  gives  [19 10]  the  laws  passed  in  several  West 
Indian  Colonies.  From  my  experience  (in  1896  I  was  a  member  of 
a  committee  which  reformed  the  municipal  laws  in  the  station  of 
Bangalore  in  India),  I  do  not  think  that  all  of  them  are  very  good 
or  practicable ;  and  Boyce  admits  that  they  have  often  become  a  dead 
letter.     But  I  quote  some  of  the  clauses  as  examples. 

"  The  occupier  or  owner  of  any  premises  shall  keep  such  premises 
free  of  stagnant  water  liable  to  breed  mosquitos,  and  the  presence  of 
mosquito  larvae  in  any  collection  of  water,  wherever  situated,  shall  be 
sufficient  evidence  that  such  water  is  stagnant."  Accepted  in  most  of 
the  colonies — a  simple  and  inclusive  clause. 

^  Some  specific  provision  ought  to  be  made  to  enable  the  sanitary  authority  to  fill 
up  with  concrete,  or  otherwise  to  treat,  holes  and  hollows  in  trees  which  breed,  or  are 
likely  to  breed,  mosquitos  ;  and  also  to  compel  owners  to  cut  insanitary  undergrowth. 


638  NOTES  [Sect. 

"  The  owner,  or  when  required  by  the  local  authority,  the  occupier 
of  every  lot  of  land  situate  in  a  town  or  village  district  shall  effectually 
drain  the  lot,  and  for  that  purpose  shall  (i)  make  such  dams  and 
drains  on  the  lot  as  may  be  necessary  for  effectually  draining  the  lot ; 
(2)  fill  up  all  irregularities  on  the  surface  of  the  lot,  and  adjust  the 
surface  thereof,  and  if  necessary  raise  the  level  of  the  surface  thereof, 
in  such  a  manner  (a)  that  the  water  received  on  the  lot  may  flow  into 
the  drains  without  obstruction,  (d)  that  no  water  can  remain  on  any 
portion  of  the  surface  of  the  lot  other  than  the  drains,  and  (c)  that 
the  surface  of  the  lot  does  not  remain  swampy.  Provided  that  where 
the  swampy  state  of  any  lot  in  any  such  district  is  occasioned  by  the 
main  drains  into  which  the  drains  of  the  lot  discharge  not  having  a 
sufficient  outfall  or  a  sufficient  capacity  to  carry  off  all  the  water 
discharged  into  them,  the  owner  or  occupier  of  the  lot  shall  not  be 
liable  under  this  section  to  raise  the  level  of  the  surface  of  the  lot 
if  the  level  of  such  surface  is  as  high  as  the  average  height  of  the 
level  of  the  land  surrounding  such  a  lot  for  a  distance  of  20  roods 
(?  20  rods  =  110  yards.  A  rood  is  a  square  measure);  and  provided 
that  any  owner  may,  with  the  consent  of  the  local  authority  of  the 
district  in  which  the  lot  is  situated,  have  a  pond  on  the  lot."  George- 
town^ British  Guiana. 

"  All  vats,  tanks,  or  other  vessels  shall  be  screened  with  mosquito- 
proof  wire-netting  or  other  suitable  material,  so  as  to  prevent  the 
entrance  into  or  exit  of  mosquitos  from  such  vats  or  tanks  or  other 
vessels."     British  Guiana. 

Such  regulations  should,  if  possible,  be  included  in  the  general 
Health  Act,  and  not  be  left  to  the  bye-laws  of  local  bodies,  which 
are  often  very  incompetent.  In  my  opinion  British  administration 
is  generally  much  wanting  in  disciphne,  and  tends  to  neglect  the 
health  and  lives  of  the  people  for  the  sake  of  antiquated  notions 
about  the  liberty  of  the  subject. 

65.  Notes. — I  will  conclude  this  book  with  some  miscellaneous 
notes  on  points  of  interest  which  have  been  studied  while  it  was 
in  the  press. 

(i).  The  thick-film  process. — For  ordinary  microscopic  preparations, 
I  c.mm.  of  blood  is  spread  out  thinly  over,  say,  4  sq.  cms.  of  area, 
and  then  examined  either  fresh  or  stained  —  at  the  cost  of  much 
time  (section  18  (9)).  Consequently  I  proposed  the  following  method 
[1903].  A  quantity  of  blood,  say  i  c.mm.,  is  spread  over  only  about 
1/4  sq.  cm.  of  area,  and  allowed  to  dry.  The  haemoglobin  is  then 
washed  out  with  water,  and  the  residue,  consisting  of  parasites,  leukids, 
micrids  and  the  stromata  of  the  haematids,  is  stained  by  any  appro- 
priate method.     We  can  thus  search  i  c.mm.  of  blood  in  about  1/16 


65]  ADDENDA  639 

the  time,  or  less,  required  for  an  ordinary  preparation  —  but  the 
parasites,  especially  P.  vivax,  are  apt  to  be  overlooked  unless  the 
observer  trains  himself  in  the  work.  Originally  I  washed  out  the 
haemoglobin  with  water  and  then  fixed  and  stained  the  residue  as 
usual;  but  later  I  obtained  better  results  by  washing  out  with  eosin 
solution,  washing  this  off,  and  then  passing  over  a  weak  solution  of 
methylene  blue.  R.  Ruge,  however,  advocates  the  former  procedure 
[1903],  and  L.  Rogers  [1908,  p.  17]  prefers  first  to  fix  and  stain,  and 
then  to  wash  out  the  haemoglobin  with  a  very  dilute  solution  of  acetic 
acid — which  leaves  the  outline  of  the  haematids  without  obscuring  the 
view.  All  these  methods  are  useful.  Sediment  and  overstaining  of 
the  stromata  are  to  be  avoided,  and  the  film  should  not  be  too  thick. 
(2).  Eniimerative  methods. — Very  rough  ones  are  now  in  use.  We 
count  the  number  of  parasites  in  a  given  number  of  fields  of  an 
ordinary  preparation — giving  an  enormous  possible  error,  because  we 
do  not  know  the  amount  of  blood  in  each  field.  Or  we  count  the 
number  of  parasites  found  near  a  given  number  of  leukids,  the  latter 
being  counted  by  a  haemocytometer.  Here  the  total  estimate  is  the 
product  of  the  two  partial  counts ;  and  if  the  errors  contained  in  the 
latter  are  both  positive  or  both  negative  (which  should  occur  in  half 
the  estimations),  the  total  error  may  again  be  enormous.  Direct 
counting  by  the  haemacytometer  is  far  from  easy  in  the  case  of  small 
parasites,  owing  to  the  depth  of  the  fluid  examined. 

Since  the  beginning  of  this  year  (19 10),  the  Advisory  Committee  of 
the  Tropical  Diseases'  Research  Fund  (Colonial  Office)  have  granted 
considerable  funds  for  the  accurate  study  of  cases  of  malaria  in 
Liverpool,  and  Dr  David  Thomson  and  myself  have  commenced  this 
study  by  elaborating  improved  "  enumerative  methods  "  based  on  my 
thick-film  process.  A  measured  quantity  of  undiluted  blood  is  made 
into  a  thick-film  preparation,  and  the  total  number  of  parasites  con- 
tained in  the  whole  of  it  is  carefully  counted.  The  quantity  of  blood 
used  is  measured  by  means  of  a  graduated  pipette  or  capillary  tube. 
It  is  necessary  that  this  tube  should  have  a  very  fine  calibre  to  allow 
a  small  quantity  of  blood,  such  as  i  c.mm.,  to  occupy  a  sufficient 
length  of  the  tube  to  permit  of  accurate  measurements  being  made. 
Thus  a  tube  of  i8o/x  in  diameter,  and  of  4  cm.  in  length,  will 
contain  I'oiS  c.mm.  (say  i  c.mm.)  of  blood.  Dr  Wakelin  Barratt 
points  out  that  any  one  can  make  a  suitable  pipette  by  drawing  out  a  fine 
capillary  glass  tube,  measuring  its  calibre  by  the  microscope,  and 
calculating  the  length  required  to  contain  the  given  volume  (area  of 


640  NOTES  [Sect. 

circle  =  square  of  diameter  x  by  o'7854,  and  area  of  ellipse  =  product 
of  the  two  diameters  x  by  the  same  figure).  We  are,  however,  making 
special  tubes,  measuring  1/4  c.mm.  or  more, 

Mr  M.  Greenwood,  Jr.,  of  the  Lister  Institute,  informs  me  that  the 
percentage  of  error  is  e%  =  67"449  /  Jn  where  n  is  the  number  of 
bodies  actually  counted  in  the  measured  quantity  of  blood.  Thus  the 
error=i%  if  we  have  counted  4,550  bodies,  2%  for  1,138  bodies,  5% 
for  182  bodies,  and  10%  for  46  bodies.  We  must  therefore  always 
count  enough  bodies  (parasites  or  leukids)  to  reduce  the  error  to  any 
required  percentage.  Hence  the  measured  quantity  of  blood  should 
be  small  when  the  parasites  are  numerous,  and  large  when  they  are 
scarce.  We  should  perhaps  allow  5%  error  for  the  measurement  of 
the  blood,  especially  when  very  small  quantities  are  taken.  First 
sample  should  be  rejected,  and  fixing  before  staining  is  demanded  in 
order  to  avoid  loss.     The  method  is  excellent  for  leukids. 

(3).  Some  results. — Applied  to  a  case  of  sleeping  sickness  this  method 
disclosed,  besides  other  facts,  a  regular  periodic  rise  and  fall  in  the 
number  of  trypanosomes  occurring  every  seven  to  eight  days  —  a 
phenomenon  apparently  not  previously  detected  {^Proceedings  of  the 
Royal  Society,  June  19 10).  With  twenty-five  cases  of  malaria  some 
of  our  results  are,  briefly,  as  follows  : — 

When  fewer  than  about  1,000  per  c.mm.,  the  sporids  are  not  always 
numerous  enough  to  cause  marked  rise  of  temperature  (section  18  (8)). 
They  may  remain  present  in  very  small  but  detectable  numbers  during 
every  day  between  relapses.  A  rise  in  their  numbers  to  about  1,000  or 
more  is  generally  accompanied  by  a  febrile  relapse  and  followed  by  a 
fall  in  haemoglobin.  A  fall  in  the  number  of  malignant  sporids  may  be 
followed  by  such  an  abrupt  and  high  rise  that  the  said  fall  cannot  be 
due  to  the  death  of  the  parasites,  but  must  be  caused  by  their  retire- 
ment from  the  peripheral  blood  —  thus  proving  the  hypothesis  of 
Marchiafava  and  Bignami.  Relapses  may  occur  without  a  single 
crescent  being  found  even  after  daily  thick-film  examinations  made 
during  twenty-nine  days ;  and  the  number  of  sporids  counted  during 
such  relapses  cannot  be  explained  by  parthenogenic  reproduction, 
unless  we  suppose  that  each  crescent  can  produce  some  hundreds  of 
spores.  A  rise  in  the  sporid  curve  is  often  followed  after  eight  to  ten 
days  by  a  corresponding  rise  in  the  crescent  curve,  suggesting  that  the 
latter  require  this  period  for  development  from  the  former;  but  some- 
times no  crescents  at  all  are  produced,  even  without  quinine ;  or  else 
the  gamogenesis   commences   or   ceases   suddenly.     The   rise  of  the 


6s]  ADDENDA  641 

crescent  curve  may  be  very  rapid  and  continuous.  The  fall  may  be 
equally  rapid  at  first,  but  often  alternates  with  short  rises — suggesting 
continuous  death  and  reproduction ;  but  later  the  fall  tends  to  be  more 
gradual.  Quinine  (even  in  2  gramme  daily  doses  in  a  boy),  soamine 
and  methylene  blue  had  no  very  decisive  effect  on  the  crescents 
when  once  formed.  The  crescents  have  never  numbered  more  than 
1/8  the  highest  number  of  sporids.  Of  the  latter  (malignant), 
300,000  was  the  largest  number  found  per  c.mm.  G.  C.  E.  Simpson, 
working  with  us,  has  demonstrated  parallel  fluctuations  of  urobilin 
in  urine  and  faeces.  Faradic  and  galvanic  currents  applied  to  the 
spleen  did  not  increase  the  number  of  crescents  in  the  peripheral 
blood,  and  X-rays  to  the  spleen  did  not  prevent  a  relapse.  (Compare 
Chapter  IV.) 

The  method  gives  at  the  same  time  much  more  accurate  diagnosis, 
and  is  useful  for  obtaining  the  parasite  rate  (section  51). 

(4).  S.  T.  Darling  has  recently  done  some  good  enumerative  work 
at  Panama,  partly  pubUshed  [1909]  and  partly  just  communicated  to 
me  by  letter  [1910].  He  counted  the  number  of  crescents  in  patients 
(by  comparison  with  leucocytes),  fed  Anophelines  on  them,  and  then 
counted  the  zygotes  in  the  insects ;  and  estimates  that  the  mortality 
of  the  parasites  in  the  stomach  cavity  is  97%  (section  18  (i)).  A. 
albimana,  bred  in  laboratory,  weighed  o"ooo8  grammes  before  feeding 
and  o'ooi6  grammes  after  a  moderate  blood  meal.  He  takes  the  average 
blood-meal  to  weigh  about  one  milligramme,  and  from  the  number 
of  gametids  counted  in  the  blood,  he  estimates  the  number  which 
must  have  been  ingested  during  the  meal.  This  he  compares  with 
the  number  of  zygotes  actually  found.  For  example,  he  estimated 
that  one  mosquito  should  have  contained  1,632  zygotes  after  three 
feedings  :  but  it  contained  only  fifty.  He  thinks  that  fully  half  the 
ingested  gametids  are  captured  by  leukids  in  the  insect's  stomach — 
as  I  showed  in  1895.  In  one  mosquito  he  found  168  zygotes.  He 
concludes  that  if  the  gametids  in  a  patient's  blood  are  less  than  about 
12  per  c.mm.  they  will  not  be  numerous  enough  to  infect  mosquitos. 
After  experiments  on  "  a  number  of  patients,"  he  thinks  that  30  grains 
of  quinine  taken  daily  will  reduce  the  number  of  crescents  (section  23). 
We  have  seen,  however,  that  the  crescent  curve  may  fall  quite  irregularly, 
and  sometimes  vary  rapidly,  without  any  quinine. 

At  my  suggestion  my  brother,  E.  H.  Ross,  recently  carried  out 
the  following  experiments  at  Port  Said,  in  parts  from  which  mosquitos 
have  been  entirely  banished  :  344  Culex  fatigans,  males  and  females, 

2  S 


642  NOTES  [Sect. 

were  liberated  from  bottles  in  houses  free  from  mosquitos,  and  search 
was  made  to  ascertain  what  became  of  them.  Only  54,  or  16%,  were 
found,  mostly  dead,  during  the  next  day  or  two,  after  which  the 
remainder  disappeared  entirely.  Only  three  persons  were  bitten  after 
the  experiment — suggesting  that  the  biting  ratio  (section  29  (3))  is 
very  low,  say  1/50. 

(5).  We  have  found  three  more  successful  mosquito  inoculations 
of  man,  bringing  the  number  up  to  38  (section  17). 

Case  36,  J.  Tsuzuki  [1902]. — Source,  benign  tertian.  One  of 
many  infected  Myzorh.  sinensis  bit  healthy  subject  in  Sapporo,  Jeso, 
Japan,  which  is  free  of  malaria  on  24th  August  (?)  1901.  Fever  and 
parasites  on  31st  August. 

Case  37.  N.  Jansco  [1903]. — Source,  malignant.  A.  daviger 
(?  Meig.)  bit  subject  on  6th  December  1907  in  Hungary.  One  gramme 
sulphate  of  quinine  given  on  seventh  and  eighth  day  after  inoculation. 
Fever  and  parasites  on   18th  December. 

Case  38.  Ibid. — Same  source  and  one  A.  daviger.  Subject  given 
same  dose  of  quinine  on  eighth,  ninth  and  tenth  days  after  inoculation 
on  20th  and  25th  October  (?  year).  Fever  on  4th  November  and 
parasites  on  the  5  th. 

Jansc6  also  records  three  interesting  negative  cases  obtained  at  the 
same  time.  Case  i  received  i  gramme  of  quinine  daily  from  the 
second  to  the  fourteenth  day  after  inoculation,  and  remained  well 
during  nine  months'  incubation.  Case  2  received  1/2  gramme  every 
morning  on  an  empty  stomach  from  ten  hours  before  inoculation  to 
the  thirteenth  day  afterwards,  and  remained  well  during  one  month's 
observation.  Case  3  received  i"5  grammes  quinine  on  fourth,  fifth, 
ninth,  tenth,  fourteenth  and  fifteenth  days  after  inoculation,  and  had  no 
fever  during  one  month's  observation. 

M.  Glogner  [1905]  records  two  cases  which  he  thinks  were  due  to 
inoculation  during  vaccination. 

(6).  With  reference  to  the  attitude  of  Anophelines,  Mr  Theobald 
informs  me  that  the  only  species  known  to  him  of  which  the  larva 
suspends  itself  in  water  like  a  Culicine  larva  is  Myzomyia  azriki 
Patton,  1905  ;  and  that  Myzomyia  culidfades  is  the  only  one  of  which 
the  adult  has  an  abnormal  attitude  So  far  as  he  knows  the  larvae  of 
all  the  species  have  no  siphon. 


65]  ADDENDA  643 

(7).  Regarding  the  enumeration  of  mosquitos  (section  29  (4)),  I 
forgot  to  mention  a  method  used  at  Panama  and  elsewhere  which 
consists  in  keeping  note  of  the  number  of  breeding-places  found  from 
time  to  time.  It  is,  of  course,  a  very  vague  method,  but  has  the 
advantage  of  being  easily  practised  by  the  working  gangs  or  moustiquiers. 
Such  records  give  them  no  additional  trouble  and  serve  for  a  check 
upon  their  work. 

(8).  A.  Eysell  in  the  Archiv.  fur  Schiffs  und  Tropai  Hygiene, 
Band  XIV.,  19 10,  argues  that  M.  rossii  is  the  same  as  the  malaria 
bearing  mosquitos  of  Kinoshita  and  also  of  Schiiffner. 

(9).  Colonel  W.  G.  King,  the  distinguished  Sanitary  Commissioner 
of  Madras  and  Burma,  informs  me  that  from  estimates  which  he  has 
made  regarding  the  cost  of  death  and  of  sickness  in  India,  he  finds 
that  the  death  of  an  adult  costs  Rs.20;  of  a  child  Rs.7  ;  while  a 
month's  sickness  of  an  adult  costs  Rs.9.  and  of  a  child  Rs.4'5.  As 
there  are  quite  1,000,000  deaths  from  malaria  every  year  in  India,  with  a 
corresponding  amount  of  sickness,  the  total  cost  of  the  disease  may  be 
roughly  computed  from  these  figures. 

(10).  Some  time  ago  I  asked  Professor  Karl  Pearson  to  assist  me 
with  the  calculations  regarding  the  diffusion  of  malaria  given  in 
Chapter  V  of  this  book.  He  requested  Mr  H.  Waite  to  undertake  the 
work.  Unfortunately  Mr  Waite  was  not  able  to  complete  his  studies  until 
this  book  was  finished ;  but  I  have  now  seen  the  proof  of  his  paper — 
which  I  hope  will  appear  in  Biometrika.  Mr  Waite  proceeds  on  the 
basis  given  in  my  report  on  Mauritius  and  in  section  2  7  ;  and  it  is  very 
important  to  note  that  his  general  conclusions  are  the  same  as  those 
obtained  independently  by  me  and  given  in  section  28 ;  that  is  to  say, 
that  the  malaria  rate  in  a  locality  will  fall  or  rise  to  a  definite  stable 
figure  depending  upon  the  average  proportion  of  Anophelines  present. 


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1898  Bastianelli  (G.),  Bignami  (A.),  and  Grassi  (B.).     "  Coltivazione  delle 

semilune  malariche  dell'uomo  nell'  Anopheles  claviger  Fabr." 
(Sinonimo :  Anopheles  maculipennis  Meig.).  Inviata  il :  28th 
November  1898.  Atti.  della  R.  Accad.  del  Lincei,  1898,  VII., 
P-  313- 

Bignami  (A.).  "  Come  si  prendono  le  febbri  malariche.  Richerche 
speriment."  Bull,  della  R.  Accad.  med.  di  Roma,  15th  November 
1898  ;  also,  Lancet,  3rd  and  loth  December  1898. 

Bignami  (A.).  "  Sulla  questione  della  malaria  congenita."  // 
Policlinico,  1898. 


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1898  Bignami    (A.).     "Due    casi    di    terzana    estiva    sperimentale."     // 

Policlinico,  1898. 

Grassi  (B.)-  "  Rapporti  tra  la  malaria  e  peculiari  insetti."  Policlinico, 
1st  October  1898;  also  Rendic  R.  Accad.  del  Lincei^  1898,  VII., 
pp.   163-172. 

Grassi  (B.)  "La  malaria  propagata  per  mezzo  di  peculiari  insetti. 
Rendic  R.  Accad.  dei  Lined,  1898,  VII.,  pp.  234-240. 

Grassi  (B.).  "  Rapporti  tra  la  malaria  e  gli  artropodi."  Rendic 
R.  Accad.  dei  Lincei.,  1898,  VII.,  pp.  314-315. 

Manson  (P.).  "  Surgeon-Major  Ronald  Ross's  Recent  Investigations 
on  the  Mosquito- Malaria  Theory."  Brit.  Med.  Journ.,  i8th  June, 
1898,  I.  pp.  1575-1577- 

Manson  (P.).  "The  Mosquito  and  the  Malaria  Parasite."  (Read  at 
the  end  of  July.)  Brit.  Med.  Journ.,  24th  September  1898,  II., 
pp.  849-853. 

Ross  (R.).  "Further  Observations  on  the  Transformation  of 
Crescents."    Ind.  Med.  Gaz.,  January  1898,  XXXIII.,  No.  i. 

Ross  (R.).  "Pigmented  Cells  in  Mosquitos."  Brit.  Med.  Journ., 
26th  February  1898,  I. 

Ross  (R.).  Report  on  a  Preliminary  Investigation  into  Malaria  in  the 
Sigur  Ghat,  Ootacamund.  Ind.  Med.  Gas.,  April  1898,  XXXIII., 
pp.  133-136,  170-175  :  also,  Transactions  of  the  South  Indian 
Branch  Brit.  Med.  Assoc,  February  1898. 

Ross  (R.).  Preliminary  Report  on  the  Infection  of  Birds  with 
Proteosoma  by  the  Bites  of  Mosquitos.  Dated  nth  October 
1898.     Government  Press,  Calcutta. 

Ross  (R.).  Report  on  the  Cultivation  of  Proteosoma,  Labbe,  in 
Grey  Mosquitos.  Government  Press,  Calcutta  (dated  21st  May 
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Thayer  (W.  S.).  "  Lectures  on  the  Malarial  Fevers."  Henry 
Kimpton,  London,  1898. 

1899  Bastianelli  (G.)  and  Bignami  (A.).     "  Sullo  sviluppo  dei  parassiti  della 

terzana   nell' Anopheles   claviger."     Atti  d.    Soc.  per  gli  studi  d. 
7nala>ia,  1899,  I.,  pp.  28-49. 

Daniels  (C.  W.).  "  On  Transmission  of  Proteosoma  to  Birds  by 
Mosquitos."     Royal  Society,  i6th  March  1899. 

Elting  (A.  W.).  "  ijber  Malaria  nach  experimentellen  Impfungen." 
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1899  Grassi  (B.),  Bignami  (A.),  and  Bastianelli  (G.).  "  Ciclo  evolutive 
delle  semilune  nell'Anopheles  claviger  ed  altri  studi  sulla  Malaria 
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malaria,  1899,  I.,  pp.  14-27. 

Koch  (R.).     tJber  die  Entwickelung  der  malaria' parasiten."     Zeitschr. 
f.  hygiene,  1899,  XXXII. 

Koch  (R.).  "Ergebnisse  der  wissenschaftlichen  Expedition  nach 
Italien  zur  Forschung  der  Malaria."  Deiitsch.  Med.  Woch,, 
2nd  February  1899,  XXV.,  5,  pp.  69-70. 

Nuttall  (G.  H.  F.).  "On  the  Role  of  Insects,  Arachnids  and 
Myriapods,  as  Carriers  in  the  Spread  of  Bacterial  and  Parasitic 
Diseases  of  Man  and  Animals."  Johns  Hopkins  Hospital  Reports, 
1899,  VIII.  ;  also,  Hygien.  Rundschau,  1899. 

Nuttall  (G.  H.  F.).  "Die  Mosquito-Malaria  Theorie."  Centralbl f. 
Bakt.,  1899,  XXV.,  No.  5,  p.  161  ;  6,  p.  209  ;  7,  p.  245  ;  8,  9,  p. 
285  ;   10,  p.    337  ;  24,  p.  877  ;  25,  p.  903  ;  and  XXVI.,  4,  5,  p.  140. 

Ross  (R.).  "  Du  Role  des  Moustiques  dans  le  Paludisme."  Ann.  Inst. 
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Ross  (R.).  Report  on  Kala  -  azar  (dated  30th  January  1899). 
Government  Press,  Calcutta,  1899. 

Ross  (R.).  "Extermination  of  Malaria"  (dated  i6th  February  1899). 
Ind.  Med.  Gaz.,  July  1899. 

Ross  (R.).  "The  Possibility  of  Extirpating  Malaria  from  Certain 
Localities  by  a  New  Method."  Brit.  Med.  Journ.,  ist  July  1899, 
II.,  p.  I. 

Ross  (R.).  "  An  Outbreak  of  Fever  attributed  to  Mosquitos."  Brit. 
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Ross  (R.).  "  Life  History  of  the  Parasites  of  Malaria."  Nature, 
3rd  August  1899. 

Correspondent  (R.  Ross).  "The  Malaria  Expedition  to  Sierra 
Leone."  Brit.  Med.  Journ.,  9th,  i6th,  30th  September  and  14th 
October  1899. 

Ross  (R.).  "  Malarial  Fever  :  Its  Cause,  Prevention,  and  Treatment." 
Liverpool  Sch.  Trop.  Med.,  Memoir  I.,  1899. 

1899-    Stephens    (J.    W.    W.)   and    Christophers   (S.  R.).      Reports  to  the 
1903  Malaria  Committee  of  the  Royal  Society,  1899-1903. 

1900  Daniels  (C.  W.).  "Development  of  Crescents  in  the  Small  Dark 
Anopheles  prevalent  in  British  Central  Africa."  Rep.  Mai.  Com, 
Royal  Soc,  1901,  Series  V.,  pp.  41-44. 


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1900     Fermi   (C.)   and    Lumbau   (S.)-     "  Befreiung  einer    Stadt  von  den 
Mucken."     Centralbl.  f.  Bakt.  I.  Abt.,  1900,  XXVIII.,  pp.  179,  185. 

Gosio  (B.).  "La  malaria  di  Crosseto  nell'anno,  1899."  Estratto 
dal :  Policlinico,  1900,  VI I -M. 

Grassi  (B.).  "  Studi  di  uno  zoologo  sulla  malaria."  R.  Accad.  d. 
Lincei,  4th  June  1900. 

Koch  (R.).  "Berichte  iiber  die  Tatigkeit  der  Malaria  expedition." 
Deutsch.  Med.  IVock.,  1899,  No.  27  5  iQoo,  Nos.  5,  17,  18,  25,  34, 
and  46 ;  also,  Br/^.  Med.  Journ.,  loth  February,  12th  May, 
30th  June. 

Koch  (R.).  "  Zusammenfassende  Darstellung  der  Ergebnisse  der 
Malaria  Expedition."     Deutsch.  Med.  JVoc/i.,  1900,  No.  49. 

Manson  (P.).  "  Experimental  Proof  of  the  Mosquito  -  Malaria 
Theory."    Bnf.  Med.  Joiirm..,  29th  September  1900,  II.,  pp.  949-951. 

Rees  (D.  C).  "  Experimental  Proof  of  the  Malaria-Mosquito  Theory." 
Brit.  Med.  Journ..,  6th  October  1900,  II.,  pp.  1054-1055. 

Ross  (R.),  Annett  (H.  E.),  and  Austen  (E.  E.).  Report  of  the  Malaria 
Expedition  of  the  Liverpool  School  of  Tropical  Medicine. 
University  Press  of  Liverpool.     Memoir  II.,  February  1900. 

Scheer  (A.  van  der)  and  Berdenis  van  Berlekom  (J.).  "  Malaria  and 
Mosquitos  in  Zealand."  Ned.  Tydschr.  v.  Ceneesk,  24th  February 
and  14th  July  1900;  also  Brit.  Med.  Jou7-n..,  26\.h.  January  1901, 
I.,  pp.  200-202. 

Stephens  (J.  W.  W.)  and  Christophers  (S.  R.).  Reports  to  the  Malaria 
Committee  of  the  Royal  Society,  1899-1903. 

Various  Authors  :  Liverpool  School  of  Tropical  Medicine.,  Memoirs 
II.,  III.,  IV.  ;  and  Royal  Society  Reports  to  the  Malaria  Com- 
mittee, 6th  July  and  15th  August  1900. 

1900-   Thomson   (J.    C).     "  Malaria   Prevention   in  Hong-Kong."     Official 
1903  Report,  containing  many  letters. 

1900-    Reports  on  the  Health  and  Sanitary  Conditions  of  the  Colony  of 
1905  Hong-Kong,  1900-1905. 

1901  Billet  (A.).  "  Sur  la  presence  constante  de  I'hematozoaire  de  Laveran 
dans  le  paludisme  en  Algerie"  (Constantine).  Compt.  Rend.  Soc. 
Biol..,  December  1901,  LIII.  pp.  1063-1065. 

Celli  (A.).  "  Malaria  according  to  the  New  Researches."  Longmans, 
Green  &  Co.,  London,  1901. 

Ewing  (J.).  "Malarial  Parasitology."  Journ.  of  Exp.  Med..,  25th 
March  1901,  V.,  5,  p.  429. 


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1901     Ewing  (J.).    "  A  Case  of  Malarial  Nephritis  with  Massing  of  Parasites 
in  the  Kidney."    Am.  Journ.  of  the  Med.  Sc,  1901,  CXXII.  p.  426. 

Fearnside  (C.  F.).  "The  Inoculation  of  Malaria  by  Anophele."  Brz't. 
Med.  Journ.,  14th  September  1901,  No.  2124,  pp.  686-687.  Scient. 
Mem.  of  Med.  Of.  India.,  Part  XIII.,  1901.  (Paper  dated  27th 
January  1901.) 

Grassi  (B.).  "  Die  Malaria.  Studien  eines  Zoologen."  2te  vermehrte 
Auflage.     Jena,  igoi. 

Gualdi  (T.)  and  Martirano  (F.).  "L'azione  della  chinina  sulle 
semilune."     Atti  d.  Sac.  per  gli  studi  d.  malaria,  1901,  II.  pp.  1-5. 

Howard  (L.  O.).  "  Mosquitos."  New  York,  June  1901.  M'Clure, 
Phillips  &  Co. 

Kleine  (F.  K.).  "  Uber  die  Resorption  von  Chininsalzen."  Zeitschr.  f. 
Hyg.,  1901,  XXXVIII.,  3,  pp.  458-471- 

M'Gregor  (W.).  "  Notes  on  Anti-malarial  Measures  now  being  taken 
in  Lagos."    Brit.  Med.  Journ.,  14th  September  1901,  II.,  p.  680-682. 

Nuttall  (G.  H.  F.),  Cobbett  (L.),  and  Strangeways-Pigg  (T.).  "The 
Geographical  Distribution  of  Anopheles  in  Relation  to  the  Former 
Distribution  of  Ague  in  England."  Journ.  of  Hygiene,  January 
1901,  I.,  I,  pp.  4-44. 

Rogers  (L.).  "  The  Seasonal  Prevalence  of  Anopheles  and  Malarial 
Fever  in  Lower  Bengal  ;  and  the  Practical  Application  of  the 
Mosquito  Theory."  Journ.  of  Hygiene,  October  1901,  I.,  4, 
pp.  407-421. 

Ross  (R.).  "First  Progress  Report  of  the  Campaign  against  Mosquitos 
in  Sierra  Leone,  with  Letter  by  Daniels."  Liverpool  Sch.  of  Trap. 
Med.,  Memoir  V.,  Part  I,  15th  October  1901. 

Ruge  (R.).  "  Untersuchungen  liber  das  deutsche  Proteosoma." 
Centralbl.f  Bakt,  1901,  I.  Abt.,  XXIX.,  5,  p.  187. 

Stephens  (J.  W.  W.),  Christophers  (S.  R.),  and  James  (S.  P.).  "  Note 
on  the  Occurrence  of  Anopheles  funestus  and  Anopheles  costalis 
in  India."     Ind.  Med.  Gas.,  October  1901,  XXXVI.,  p.  361. 

Theobald  (F.  V.).  "  The  Classification  of  Mosquitos."  Journ.  Trop. 
Med.,  15th  July  1901,  IV.,  14,  pp.  229-235. 

Theobald  (F.  V.).  "  A  Monograph  of  the  Culicidae  or  Mosquitos." 
London,  1901. 

Thomson  (J.  C).  "The  Distribution  of  Anopheles  and  Culex  at  Hong- 
Kong."    Brit.  Med.  Journ.,  15th  January  1901,  I.,  pp.  749  and  1379. 

Young  (J.  M.).  "A  Discussion  on  Malaria  and  its  Prevention."  III. 
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14th  September  1901,  II.,  pp.  683-686. 


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1902  Annett  (H.  E.),  Button  (J.  E.),  and  Elliott  (J.  H.)-  Report  of  the 
Malaria  Expedition  to  Nigeria.  Liverpool  Sch.  Trap.  Med., 
Memoir  III.,  1902. 

Blasi  (A.  de).  "  II  bleu  metileno  nella  malaria."  Gaz.  degli  Ospedali 
e  delle  clhi.,  i6th  and  23rd  March  1902. 

Caccini  (A.).  "  The  Duration  of  the  Latency  of  Malaria  after  Primary 
Infection,"  etc.    Joiirn.  Trop.  Med.,  1902,  Nos.  8,  9,  10,  11  and  12. 

Caccini  (A.).  "  Sullo  sviluppo  e  sul  decorso  delle  epidemie  malariche 
degli  anni  1900-1901  studiate  nell'  Ospedale  di  S.  Spirito."  Atti, 
1902,  III.,  pp.  356-366. 

Celli  (A.).  "  Stato  palustre  ed  anofelico  (paludisme)  senza  malaria." 
Atti  della  Soc.  per gli  studi  d.  malaria,  1902,  III.,  pp.  115-145. 

Chalmers  (A.  J.).  "A  Theory  to  explain  how  Man  and  the  Anopheles 
originally  became  infected  with  the  Malarial  Germ."  Jou?'n.  Trop. 
Med.,  1st  May  1902,  V.,  9,  pp.  133-134. 

Button  (J.  E.).  Report  of  the  Malaria  Expedition  to  the  Gambia, 
1902.  Liverpool  Sch.  Trop.  Med.,  Memoir  X.  Longmans,  Green 
and  Co.,  London,  1903. 

Maurer  (G.).  "Die  Malaria  Perniciosa."  Centralbl.  f.  Bakt.  Otig., 
5th  November  1902,  XXXII.,  p.  695. 

Nuttall  (G.  H.  F.)  and  Shipley  (A.  E.).  "The  Structure  and  Biology 
of  Anopheles  {A.  tiiaculipemtis).'"  Joiirn.  of  Hygietie,  January 
1901  ;  April  1901  ;  October  1901  ;  January  1902  ;  April  1903. 

Panse  (O.).  "  Bie  Malaria  unter  Eingeborenen  in  Tanga."  Arch.f. 
Schiffs  und  Trop.  Hyg.,  1902,  VI.,  12,  pp.  403-427. 

Ross  (R.).  "  Mosquito  Brigades,  and  how  to  organise  them."  George 
Philip  &  Son,  London,  1902.     98  pages. 

Sambon  (L.  W.)  and  Low  (G.  C).  Report  on  two  Experiments  on 
the  Mosquito-Malaria  Theory.  Medico-Chirurgical  Trans.,  1902, 
LXXXIV. 

Schaudinn  (F.).  "  Studien  iiber  krankheitserregende  Protozoen.  I. 
Cyclospora  caryolytica  Schaud.,  der  Erreger  der  perniciosen 
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Schiiffner  (W.).  "  Die  Beziehungen  der  Malariaparasiten  zu  Mensch 
und  Miicke  an  der  Ostkiiste  Sumatras."  Zeitschr.  f.  Hyg.  und 
Inf.,  1902,  XLL,  p.  89. 

Schiiffner  (W.).  "  Uber  die  Malariaparasiten  im  Anopheles  an  der 
Ostkiiste  von  Sumatra."  Geneesk.  Tydsckr.  v.  Ned.  Ind.,  1902, 
XLIL,  pp.  8-13. 


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1902  Stephens  (J.  W.  W.)  and  Christophers  (S.  R.).     Reports  from  India. 

III.  "The  Relation  of  Species  of  Anopheles  to  Malaria  Endemicity.'' 
Further  Report  (received  25th  April  1902).  IV.  "An  Investiga- 
tion into  the  Factors  which  determine  Malaria  Endemicity." 
(Received  25th  April  1902.)  Reports  to  the  Malaria  Committee, 
15th  August  1902,  pp.  20-45. 

Taylor  (M.  L.).  Second  Progress  Report  of  the  Campaign  against 
Mosquitos  in  Sierra  Leone  (dated  15th  September  1902). 
Liverpool  Sch.  Trop.  Med.,  Memoir,  1902,  V.,  Part  2. 

Tsuzuki  (J.).  "Malaria  und  ihre  Vermittler  in  Japan."  Arch.  f. 
Schiffs  und  Trop.  Hyg.^  1902,  VI.,  9,  pp.  285-295. 

1903  Adie  (J.  R.).     "  A  Note  on  Anopheles  fuliginosus  and  sporozoites." 

Ind.  Med.  Gaz.,  July  1903,  XXXVI II.,  pp.  246-249. 

Billet  (A.).  "  Sur  une  espece  nouvelle  d'Anopheles  {A.  chaudoyei, 
Theo.)  et  sa  relation  avec  le  paludisme  a  Touggourt  (Sud- 
Constantinois)."     Compt.  Rend.  Soc.  Biol..,  1903;  LV.,  pp.  565-567. 

Buchanan  (A.).  "  Malaria  Fevers  and  Malaria  Parasites  in  India." 
2nd  Edition,  1903. 

Celli  (A.).  Thirteenth  International  Congress  of  Hygiene  and  Demo- 
graphy at  Brussels. 

Chaudoye  and  Billet  (A.).  "La  Malaria  a  Touggourt  nel  1902,  e 
descrizione  delle  zanzare  di  Touggourt."  Giornale  ined.  del  R. 
esercito,  i^o^, /asc.  12. 

James  (S.  P.).  First  Report  on  the  anti-Malarial  Operations  in  Mian 
Mir.  Scient.  Mem.  Off.  of  the  Med.  and  Sanit.  Dep.  for  the 
Governmetit  of  India.,  I903)  No.  6. 

Jacoangeli  (T.).  "SuU'assorbimento  della  chinina  in  forma  di  tabloidi." 
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Jansco  (N.).  "  Uber  eine  in  der  Universitatsklinik  entstandene 
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1903,  LXXVL,  4-5,  pp.  474-502. 

Lutz  (A.).  "  Waldmosquitos  und  Waldmalaria."  Centralbl.f  Bakt., 
1903,  XXXIII.,  pp.  282-292. 

Mariani  (F).  "SuU'assorbimento  e  suU'eliminazione  della  chinina 
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Ross  (R.).  "  An  Improved  Method  for  the  Microscopical  Diagnosis  of 
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Ross  (R.).  Report  on  Malaria  at  Ismailia  and  Suez.  Liverpool  Sch.  of 
Trop.  Med.,  Memoir,  January  1903,  IX. 


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1903     Ross  (R.).    "The  Thick  Film  Process  for  the  Detection  of  Organisms 
in  the  Blood."    Thomson  Yates  Reports,  1903,  V.,  Part  I. 

Ruge(R.)-  Zur  Erleichterung  der  mikroskopischen  Malaria-diagnose. 
Deutsch.  Med.  JVoc/i.,  19th  March  1903,  XXIX.,  No.  12,  p.  205. 

Schaudinn  (F.).  " Studien  iiber  krankheitserregende  Protozoen."  II. 
"Plasmodium  vivax  (Grassi  and  Feletti),  derErreger  des  Tertian- 
fiebers  beim  Menschen."  Arbeit  a.  d.  Kais.  Gesundh.,  1903, 
XIX.,  p.  169. 

Watson  (M.).  "The  Effect  of  Drainage  and  other  Measures  on  the 
Malaria  of  Klang,  Federated  Malay  States."  Journ.  Trap.  Med.., 
16th  November  1903,  VI.,  22,  pp.  349-353;  and  ist  December  1903, 
VI.,  23,  pp.  368-371. 

Travers  (E.  A.  O.).  An  Account  of  Anti-Malarial  Work  carried  out 
with  Success  in  Selangor,  one  of  the  Federated  States  of  the 
Malay  Peninsula."  Journ.  Trop.  Med.,  15th  September  1903,  VI., 
18,  pp.  283-285. 

1904     Boyce  (R.).    "The  Anti-Malaria  Measures  at  Ismailia."    Liverpool 
Sch.   Trop.  Med..,  Memoir,  1904,  XII. 

Christophers  (S.  R.).  Second  Report  of  the  Anti-Malarial  Operations 
at  Mian  Mir.  Scient.  Mem.  Off.  of  the  Med.  and  Sanit.  Dept.for 
the  Government  of  India.,  1904,  No.  9. 

Giles  (G.  M.).  "Cold  Weather  Mosquito  Notes  from  India— Malaria 
in  Umtritzar  and  its  Causes."  Journ.  Trop.  Med..,  ist  April  1904, 
VII.,  7,  pp.  104-108  ;  and  15th  April  1904,  VII.,  8,  pp.  120-123. 

Hirschberg  (I.  L.  K.).  "An  Anopheles  Mosquito  which  does  not 
transmit  Malaria."     The  Johns  Hopk.  Hosp.  Bull..,  February  1904. 

Hope  (L.  M.).  "Notes  on  1,783  Cases  of  Malaria."  Journ.  Trop. 
Med..,  15th  June  1904,  VII.,  12,  pp.  182-184. 

Jansco  (N.).  "Zur  Frage  der  Infection  der  Anopheles  claviger  mit 
Malariaparasiten  bei  niederer  Temperatur."  Centralbl.  f.  Bakt, 
1904,  XXXVI.,  p.  624. 

Mariani  (F.).  "SuU'azione  antiperiodica  degli  alcaloidi  secondari 
della  chinina."  Atti  d.  Soc.  per  gli  studi  d.  7nalaria,  1904, 
v.,  pp.  151-210. 

Mariani  (F.).  "  L'assorbimento  e  I'eliminazione  della  chinina  e  de' 
suoi  sali."  Atti  d.  Soc.  per  gli  studi  d.  ynalaria,  1904,  V.,  pp.  211- 
258. 

Pressat  (A.).  "  Prophylaxie  du  Paludisme  dans  I'lsthme  de  Suez." 
La  Presse  Medicale,  30th  July  1904. 


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1904  Rosenau,    Parker,    Francis  and  Beyer.     Report  of  Working  Party, 

No.  2.  Yellow  Fever  Institute,  May  1904.     Government  Printing 
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Ross  (R.).  "The  Anti-Malaria  Experiment  at  Mian  Mir."  Brit. 
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Salvage  (J.  V.).  "  Preventive  Measures  against  Malaria  in  Kandia, 
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Sewell  (E.  P.).  "The  Results  of  the  Campaign  against  Malaria  in 
Mian  Mir."  Brit.  Med.  Journ..,  17th  September  1904,  II., 
pp.  635-637. 

Smith  (F.)  and  Pearse  (A.).  "Fevers  in  Sierra  Leone"  (Mount 
Aureol),  being  a  preliminary  account  of  an  enquiry  into  the 
causes  of  the  continued  prevalence  of  ill-health  in  an  apparently 
favourably  situated  hill  station."  Journ.  of  the  R.A.M.  Corps, 
March  1904,  II.,  3,  pp.  278-282. 

Schaudinn  (F.).  "  Generations  und  Wirtswechsel  bei  Trypanosoma 
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Schaudinn  (F.).  "  Die  Malaria  in  dem  Dorfe  '  St  Michele  di  Leme'  in 
Istrien  und  ein  Versuch  zu  ihrer  Bekampfung."  Arbeit,  a.  d. 
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Strachan  (Henry).  "Discussion  on  the  Prophylaxis  of  Malaria." 
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1905  Carducci    (A.).     "  Sulla    cura  e    sulla    causa    delle    recidive    nella 

malaria."      Atti  d.    Soc.  per  gli   studi    d.    malaria,    1905,   VI., 
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R.A.M.  Corps,  1905,  V.,  pp.  274-275. 

Glogner  (M.).  tJber  zvvei  Malariaimpfungen.  Arch.  f.  Schiffs  und 
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Goeldi  (E.  A.).  Os  mosquitos  no  Pari.  Com  144  figuras  no  texto 
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Jolly  (J.)  "  Mosquitos  and  Fever  in  Susruta."  Roy.  Asiatic  Soc, 
July  1905,  p.  558. 

MacDonald  (C.  J.).  "Crete  as  a  Station,  with  a  Mosquito  Campaign 
conducted  there  in  1903."  Journ.  of  the  R.A.M.  Co?ps,  January 
1905,  IV.,  I,  pp.  31-45. 


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Patton  (W.  S.).  "  The  Culicid  Fauna  of  the  Aden  Hinterland."  Journ. 
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Penton  (R.  H.).  "  Egyptian  Army  :  The  Malarial  Campaign  in  the 
Soudan,  1904."  Journ.  of  the  R.A.M.  Corps.,  May  1905,  IV.,  5, 
pp.  628-633. 

Pressat  (A.).  "  Le  Paludisme  et  les  Moustiques."  Masson  &  Cie, 
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Ross  (R.).  "The  Logical  Basis  of  the  Sanitary  Policy  of  Mosquito 
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Ross  (R.).  "  Researches  on  Malaria."  Les  Prix  Nobel  en  1902 
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Watson  (M.).  "The  Effect  of  Drainage  and  Other  Measures  on  the 
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Wood  (H.  C).  "  On  the  Use  of  Methylene  Blue  in  Malarial  Fever." 
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1906     Clark  (F.).     "An  Address  on  the  Prevention  of  Malaria  in   Hong- 
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Copeland  (R.  J.)  and  Smith  (F.).  "  Malarial  Fever  contracted  in 
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Craig  (C).  "Observations  upon  Malaria.  Latent  Infection  in 
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Craig  (C).      "  Intracorpuscular    Conjugation    in   the    Malarial  Plas- 
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2    T 


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Ruge  (R.).  "  Einfiihrung  in  das  Studium  der  Malariakrankheiten  mit 
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Suez  Canal  Co.  "Suppression  du  Paludisme  a  Ismailia."  Ofiicial 
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1906. 

Travers  (E.  A.  O.)  and  Watson  (M.).  "  A  Further  Report  on  Measures 
taken  in  1901  to  abolish  Malaria  from  Klang  and  Port  Swettenham 
in  Selangor,  Federated  Malay  States."  Jom-n.  Trop.  Med.,  2nd 
July  1906,  IX.,  13,  pp.  197-198. 

Ziemann  (H.).     "Malaria."     Handbuch  der  Tropenkrankheiten,  III., 

1906,  by  Dr  C.  Mense.     Leipzig,  J.  A.  Barth,  1906. 

1907  Banks  (C.  S.).  "  Experiments  in  Malarial  Transmission  by  Means  of 
Myzomyia  ludlowii  Theob."  Philipp.Jourti.  Science,  1907,  II.,  B., 
pp.  513-536. 

Giemsa  and  Schaumann.  "  Pharmakologische  und  chemisch-physio- 
logische  Studien  iiber  Chinin."     Atxh.  f.  Schiffs  und  Trop.  Hyg., 

1907,  XL,  Beiheft,  3. 

Grosch.     Med.  Klin.  No.  20. 

Husson  (  ).  "  Etudes  epidemiologiques  et  prophylactiques  sur  le 
paludisme  en  Tunisie."     Aim.  de  Plnst.  Past,  de  Tunis,  1907,  p.  3. 

Jones  (W.  H.  S.).  "  Malaria  :  a  Neglected  Factor  in  the  History  of 
Greece  and  Rome."  Chapter  by  Dr  G.  G.  Ellett  and  preface  by 
R.  Ross.     Macmillan  &  Bowes,  Cambridge,  1907. 

Laveran  (A.).  "Traite  du  Paludisme."  Masson  &  Cie,  Paris,  2nd 
edition,  1907. 

Nichols  (F.  P.).  "The  Effect  of  Large  Drainage  Works  on  the 
Prevalence  of  Malaria."  Journ.  0/ the  R. A.M.  Corps,  April  1907, 
VIIL,  4,  pp.  343-360. 


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1907  Ross  (R.)-     "An  Address  on  the  Prevention  of  Malaria  in  British 

Possessions,  Egypt,  and  Parts  of  America."  Delivered  in  Section 
VII.  of  the  14th  Internat.  Congr.  of  Hyg.  and  Demogr.  held  at 
Berlin,  September  1907.  Lancet^  28th  September  1907,  II. 
pp.  879-887. 

Sergent  (Ed.  and  Et.).  "Etudes  sur  les  hematozoaires  d'oiseaux." 
Ann.  de  PInsL  Past.,  25th  April  1907,  XXL,  4,  pp.  251-280. 

Stephens  (J.  W.  W.)  and  Christophers  (S.  R.).  "  The  Practical  Study 
of  Malaria  and  other  Blood  Parasites."    3rd  edition,  London,  1907. 

Wurtz  (R.).  "  Silicatage  des  tulles  employes  pour  proteger  contre  la 
piqure  des  moustiques."  Revue  de  Med.  ei  d'Hyg.  T7-op.,  1907, 
IV.,  4,  p.   181. 

1907-   Newstead  (R.),  Dutton  (J.  E.),  and  Todd  (L.  J.).     "  Insects  and  other 

1908  Arthropoda  collected  in  the  Congo  Free  State."     Ann.  of  Trap. 
Med.  and  ParasitoL,  1907- 1908,  I.,  p.  10. 

1908     Bliiml  (M.)  and   Merz  (G.  F.).     "  Schizogonie  der  Makrogameten." 
Arch.  f.  ScJiiffs  und  Trap.  Hyg.,  1908,  XII.,  8,  pp.  249-255. 

Fowler  (C.  E.  P.).     "  Malarial  Investigations  in  Mauritius."    London, 

1908.  Harrison  &  Sons.    Also,  _/ti«r«.  TV^/.  yI/^<^.,  15th  September 

1909,  XII.,  18,  pp.  273-275. 

Howard  (R.).  "  Malarial  Prophylaxis  in  Small  Communities  in  Brit. 
Central  Africa.'     Journ.  Trop.  Med.,  ist  January  1908,  pp.  1-16, 

Jansco  (N.),  "  L'etat  du  paludisme  en  Hongrie  pendant  les  dernieres 
annees."    Attid.  Soc.per glistudid.  malaria,  1908,  IX.,  pp.  125-150, 

Koch(R.).  "  tJber  meine  Schlafkrankheits  expedition."  Berlin,  1908, 
D.  Reimer. 

Liston  (W.  Glen).  The  "  Present  Epidemic  of  Malaria  in  the  Port  of 
Bombay."  Journ.  Bombay  Nat.  Hist.  Soc,  15th  November  1908, 
XVI 1 1.,  No.  4. 

Merz  (G.  F.)  and  Bliiml  (M.).  "Schizogonie  der  makrogameten  van 
tertianaparasieten."  (Onderzoekingen,  verricht  in  het  hospital  te 
Koeta-Radja,  September  to  December  1907.)  Geneesk.  Tydschr.  v. 
Ned.  Ind.,  1908,  XLVIIL,  2,  pp.  194-204. 

Neumann  (R.  O.).  "  Die  Ubertragung  von  Plasmodium  praecox  auf 
Kanarien-vogel  durch  Stegomyia  fasciata,  und  die  Entwicklung  der 
Parasiten  im  Magen  und  den  Speicheldriisen  dieser  Stechmiicke." 
Arch.f.  Protistenkunde,  1908,  XI 1 1.,  r,  p.  23. 

Rogers  (L.).  "  Fevers  in  the  Tropics."  Henry  Frowde,  Hodder  and 
Stoughton,  London,  1908. 


66o  REFERENCES   TO    LITERATURE 

1908  Ross  (R.).     "Report  on   the   Prevention  of  Malaria  in   Mauritius." 

London,  1908.    Waterlow  &  Sons. 

Rowan  (H.).  "  Mian  Mir  (Lahore  Cantonment)  :  A  Retrospect  and 
Prospect."  Jouf'ft.  of  the  R. A.M.  Corps,  September  1908,  XL,  3, 
pp.  229-242. 

Walter  (A.),  "  On  the  Influence  of  Forests  on  Rainfall  and  the 
Probable  Effect  of  '  Deboisement'  on  Agriculture  in  Mauritius." 
Mauritius,  Storekeeper  General's  Printing  Establ.,  1908. 

1909  Baermann  (G.),  "  Uber  Chinintod."     (Central  Hosp.,  Petoemboekan, 

Sumatra.)     Muftch.  Med.  IVoc/i.,  9th  November  1909,  No.  45. 

Boyce  (Sir  R.).     "  Mosquito  or  Man."     John  Murray,  London,  1909. 

Carter  (H.  R.).  "  Notes  on  the  Sanitation  of  Yellow  Fever  and  Malaria 
from  Isthmian  Experience."     Med.  Rec,  New  York,  loth  July  1909. 

Christophers  (S.  R.)  and  Bentley  (C.  A.),  "The  Human  Factor  in 
Malaria."  Transactions  of  the  Bombay  Medical  Congress.  The 
Times  Press,  Bombay,  1909. 

Craig  (C  F.)  "The  Malarial  Fevers,  Haemoglobinuric  Fever  and 
the  Blood  Protozoa  of  Man."     London,  1909.     J.  &  A.  Churchill. 

Daniels  (C  W.).     "  Mosquitos  in  Federated  Malay  States." 

Daniels  (C.  W.)  and  Wilkinson  (E.)  "Tropical  Medicine  and 
Hygiene."     London,  1909.     John  Bale,  Sons  and  Danielsson. 

Darling  (S.  T.).  "Transmission  of  Malarial  Fever  in  the  Canal  Zone 
by  Anopheles  Mosquitos."  Journ.  Atneric.  Med.  Assoc,  i8th 
December  1909,  LI  1 1.,  p.  2051. 

Deaderick  (W.  H.).  "  A  Practical  Study  of  Malaria."  Saunders  &  Co., 
Philadelphia,  1909. 

Easton  (P.  G.).  "  A  Case  of  Malarial  Fever  contracted  at  Aldershot," 
foiirn.  R.A.M.  Corps,  November  1909,  XI 1 1.,  5,  p.  585. 

Efifertz  (O.).  "  Malaria  in  Tropical  America  and  amongst  Indians." 
Janus,  April  1909,  p.  246. 

Genovese  (F.).  "II  clima  antico  della  Magna  Grecia  e  la  malaria 
attuale  di  Foca  (Caulonia).  Note  storiche,  profilattiche  e  demo- 
grafiche."    Atti.  d.  Soc.perglistudid.  malaria,  1909,  X.,  pp.  461-481. 

Harrison  (W.  S.).  "  On  the  Cause  of  Relapse  in  Malaria."  Joutn.  of 
the  R.A.M.  Corps,  December  1909,  XIII.,  6,  pp.  647-649. 

Jones  (W.  H.  S.).  "  Malaria  and  Greek  History."  Chapter  on  the 
history  of  Greek  therapeutics  and  the  malaria  theory  of  Dr  E.  T. 
Withington.     University  Press,  Manchester,  1909. 


NOTED    IN    SQUARE   BRACKETS  66i 

1909     King   (W.    G.)-     Information    supplied   for   the    Simla  Anti-Malaria 
Conference.     Government  Printing  Office,  Rangoon,  1909. 

Nardelli  (G.)-  "  Sulla  eliminazione  della  chinina  per  le  urine  in 
rapporto  alle  diverse  dosi  negli  individui  sani  e  malati." 
"Malaria,"  May  1909,  I.,  3,  p.  146. 

Neeb  (H.  M.).  "Parthenogenese  der  makrogameten  van  de  tropica- 
parasiet."  Geneesk.  Tydschr.  v.  Ned.  Ind.,  1909,  XLIX.,  5,  pp. 
574-584;  aXso,  Jotirn.  Trop.Med.,  ist  April  1910,  XIII.,  7, pp.  98-102. 

Ross  (R.).  "The  Campaign  against  Malaria."  (Read  at  the  meeting 
of  the  Royal  Inst,  of  Great  Britain,  7th  May  1909.)  London, 
William  Clowes  &  Sons. 

Sandro  (D.  de).  "Chinina  nei  diversi  organi."  Riforma  Medica., 
Naples,  8th  November  1909,  XXV.,  45,  pp.  1233-1260. 

Vogel  (W.  T.  de).  "  Myzomyia  rossii  als  overbrengster  der  malaria." 
Geneesk.  Tydschr.  v.  Ned.  Ind..,  1909,  XLIX.,  5,  pp.  585-595. 

1910     Bentley  (C.  A.).    "  Malaria  in  Bombay."     Government  Central  Press, 
Bombay,  19 10. 

Boyce  (R.).  "  Health  Progress  and  Administration  in  the  West 
Indies."     London,  1910.     Murray. 

Cellia  (A.).  "  Ancora  del  tannato  di  chinina  nei  casi  di  intolleranza 
d'altri  preparati  chinacei"  (Nota  2a).  "Malaria,"  January  1910, 
II.,  I,  p.  45. 

Cellia  (A.).  "  II  tannato  di  chinina  e  le  sue  indicazioni  per  la  profilassi 
e  per  la  cura  della  malaria."  "Malaria,"  March  1910,  II.,  2,  pp. 
92-103. 

Chaytor- White  (J.).  "The  Propagation  of  Small  Fish  as  a  Means  of 
Limiting  Malaria."    Proceedings  of  the  Imp.  Mai.  Coft/.i  Simla,  19 10. 

Christophers  (S.  R.).  "A  New  Statistical  Method  of  Mapping 
Epidemic  Diseases  in  India,  with  Special  Reference  to  the  Mapping 
of  Epidemic  Malaria."  Proceedings  of  the  Imp.  Mai.  Conf, 
Simla,  1910. 

Darling  (S.  T.).  "  Factors  in  the  Transmission  and  Prevention  of 
Malaria  in  the  Canal  Zone."  Afin.  Trop.  Med.  a7id  Parasitol., 
1910,  IV.,  2. 

Fernando  (H.  M.).    "  Prevention  of  Malaria  in  Ceylon."    Read  at  the 
Ceylon  Branch,  Brit.  Med.  Assoc,  19th  March  1910. 

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held  at  Simla.     Government  Press,  Simla,  1910. 


CONTENTS    IN    DETAIL 

CHAPTER   I— HISTORY 

Section 

1.  Ancient  Times,  I.     Egypt,  i.     Possible  entry  of  malaria  into  Greece 

about  550  B.C.,  I.  Knowledge  of  the  ancients  regarding  malaria,  3. 
Ceylon,  6. 

2.  Early  Modern  Times,    6.     Discovery   of  Cinchona,   6.     Theory   of 

Morton  and  Lancisi  regarding  the  paludic  miasma,  7. 

3.  Discovery  of  the  Parasites,  8.     Discovery  of  the  paludic  pigment. 

8.  Efforts  to  find  the  organism  in  marshes,  8.  Laveran  discovered 
the  parasites,  9.  Gerhardt  successfully  inoculated  man,  9.  Re- 
searches on  the  parasites,  9. 

4.  Speculations  regarding  the  Mode  of  Infection,  10.    Failure  of 

infection  experiments  with  marsh  water,  10.  Discovery  of 
metaxenyof  animal  parasites,  11.  Discoveries  regarding  Cucidanus 
elegans,  Filaria  inedinensis,  Dipylidiuiii  caninium,  Filaria  bancrofti^ 
and  Piroplasma  bigenium,  12.  Conjectures  of  Nott,  Beauperthuy, 
Finlay,  King,  Laveran,  Koch,  Manson,  15. 

5.  Researches  regarding  the  Mode  of  Infection,    20.     Negative 

researches  on  mosquito-transmission,  21.  Final  success,  23.  Dis- 
covery of  the  full  mosquito  cycle,  25. 

6.  Confirmations  and  Extensions,  26.     Koch,    Daniels,    Bignami, 

Bastianelli,  Grassi  and  others,  26. 

7.  Recent  History  of  Prevention,  29.    Early  studies  on  mosquitos,  30. 

First  proposals  regarding  mosquito  reduction,  31.  Sierra  Leone, 
34.  Later  entomological  work,  2,7-  The  quinine  method,  37.  The 
Royal  Society  Commission,  and  prevention  in  Lagos,  Sierra  Leone, 
Ismailia,  Federated  Malay  States,  Rio  Janeira,  Algeria,  and  else- 
where, 38. 

8.  Remarks,  43.     Early  neglect  of  anti-malaria  measures,  43.     Neglect 

of  recent  discoveries,  44.     Cause  of  such  neglect,  46. 
663 


664  CONTENTS    IN    DETAIL 

CHAPTER     II. —  SUMMARY     OP^     FACTS     REGARDING 
MALARIA.     (SUITABLE  FOR  PUBLIC  INSTRUCTION.) 
Section 

9.  The  Parasites  and  the  Fever,  49. 

10.  TheModeof  Infection,  51. 

11.  Facts  about  Mosquitos,  54. 

12.  Personal  Prevention,  58. 

13.  Public  Prevention,  60. 

CHAPTER  III.— THE  FUNDAMENTAL   OBSERVATIONS 
AND    EXPERIMENTS 

14.  The  Parasites  cause   the  Disease,  62.    Relations    between    the 

parasites  and  the  illness,  62. 

15.  Experimental  Blood  Inoculations,  66.    Short  description  of  51 

successful  cases  and  6  important  negative  ones,  66. 

16.  The  Parasites  develop  in  Certain  Mosquitos,  76. 

17.  Experimental  Mosquito  Inoculations,  -]•].    Experiments  on  birds 

and  35  successful  mosquito  inoculations  of  man,  79. 

CHAPTER    IV.— THE  PARASITIC    INVASION    IN    MAN 

18.  The  Onset  of  the  Invasion,  86.    (i)  The  number  of  parasites  in  the 

mosquito  86.  (2)  The  number  of  protospores  in  the  salivary 
glands,  88.  (3)  How  many  protospores  enter  the  human  blood  ? 
88.  (4)  Further  development  of  the  protospores,  88.  (5)  The 
number  of  spores  produced  by  each  species  of  parasite,  89.  (6) 
The  onset  of  the  invasion,  89.  (7)  The  number  of  haematids  in  an 
average  man,  90.  (8)  The  lowest  number  of  parasites  required  to 
produce  the  first  illness,  91.  (9)  The  time  required  to  examine  the 
blood  microscopically,  91.     (10)  The  period  of  incubation,  94. 

19.  The  Further  Progress  of  the  Invasion,  98.    (i)  Increase  of  the 

parasites,  98.  (2)  The  maximum  number  of  parasites,  99.  (3) 
Limitation  of  the  invasion,  100.  (4)  The  illness  is  due  to  a 
toxin,  loi. 

20.  The  Decline  of  the  Invasion,   104.     (i)  The  period  of  regular 

paroxysms,  104.  (2)  The  appearance  of  sexual  forms,  107.  (3) 
The  period  of  rallies  and  relapses,  108.  (4)  The  parasites  during 
the  rallies,  no.  (5)  Probable  cause  of  the  rallies  and  relapses,  115. 
(6)  Frequency  of  the  relapses,  118. 


CONTENTS    IN    DETAIL  665 

Section 

21.  Average  Duration  of  Untreated  Infections,  122. 

22.  Enlargement  of  the  Spleen  and  Liver,  127.    Some  hypotheses, 

128.  Kala-azar,  129.     Spleen  rates  in  Mauritius  and  Ceylon,  131. 

23.  The   Effect  of  Quinine,    134.     Absorption    and    eUmination,   134. 

Effect  on  the  parasites,  137.  Effect  on  relapses,  140.  Administra- 
tion and  duration  of  treatment,  141. 

24     Summary,  143. 

CHAPTER   v.— MALARIA    IN   THE  COMMUNITY 

25.  Is  the  Infection  caused  otherwise  than  by  the  Anophelines? 

145.  Several  questions  discussed,  145.  Does  malaria  come  from 
the  soil  .'^147.  Do  other  insects  carry  malaria?  149.  Do  the 
parasites  enter  the  eggs  of  mosquitos  ?  150. 

26.  Some  Definitions,  151.     Indigenous  and  imported  cases,  151.     The 

malaria  rate,  the  malaria  index,  the  inoculation  rate,  etc.,  152. 

27.  Conditions  required  for  the  Production  of  New  Infections  in  a 

Locality,  153.     Analysis,  153. 

28.  Laws  which  Regulate  the  Amount  of  Malaria  in  a  Locality,  156. 

Analysis,  156.  Formulae,  159.  Examples,  159.  The  limit  of  the 
malaria  ratio,  161. 

29.  Laws  which  Regulate  the  number  of  Anophelines  in  a  Locality, 

164.  (i)  The  output  of  mosquitos  from  marshes,  165.  (2)  The 
average  life  of  the  winged  insects,  166.  (3)  The  proportion  of 
mosquitos  which  succeed  in  biting  human  beings,  167.  (4)  The 
number  of  Anophelines  in  unit  of  area,  169.  (5)  Variation  of 
mosquito  -  density  from  place  to  place,  172.  (6)  Variation  of 
mosquito-density  from  time  to  time,  172.  (7)  Variation  of  mosquito- 
density  due  to  food,  etc.,  173.  (8)  Relation  of  mosquito-output  to 
extent  of  breeding-surface,  173.  (9)  Flock-migrations  of  mosquitos, 
176.  (10)  Visitation  of  ships,  176.  (11)  Transportation  by  ships 
and  vehicles,  177.  (12)  Transportation  by  rivers  and  wind,  177. 
(13)  Velocity  and  length  of  flights,  178.  (14)  The  random-scatter 
of  animals  from  a  given  point,  179.  (15)  Exceptions,  181.  (16) 
Diminution  of  mosquitos  round  a  central  sterile  patch,  182. 

30.  Explanation  of  Various  Phenomena,  186.    (i)  Connection  with 

marshes,  187.  (2)  Connection  with  soil,  189.  (3)  Connection 
with  slope,  189.  (4)  Connection  with  vegetation,  190.  (5)  Connec- 
tion with  rainfall,  191.  (6)  Connection  with  temperature,  192. 
(7)  Connection  with  altitude,  192.  (8)  Comparative  freedom  of 
centre  of  towns,  194.  (9)  Effect  of  density  of  human  population, 
194.  (10)  The  "regional  factor,"  195.  (11)  The  species  factor, 
196.     (12)  The  social  factor,   197.     (13)  Possible  effect  of  malaria 


666  CONTENTS    IN    DETAIL 

Section 

on  the  Anophelines,  197.  (14)  Seasonal  variation,  198.  (15) 
Annual  variation,  199.  (16)  Effect  of  imported  cases,  201.  (17) 
Isolated,  super-malarious,  or  infra-malarious  areas,  203.  (18) 
Effect  of  mass  migrations,  204.  (19)  Extraneous  infection,  205. 
(20)  Slow  changes  in  endemicity,  206.  (21)  Examples  :  Mauritius, 
Ismailia,  Clairfond,  Britain,  209.  (22)  Possible  errors  in  the 
study  of  endemicity,  214.    (23)  Remarks,  216. 

31.  The  Measurement  of  Malaria,  217.    (i)  The  parasite  rate  and  index, 

218.  (2)  The  spleen  rate  and  index,  220.  (3)  Combined  parasite 
index  and  spleen  index,  223.  (4)  Average  spleen  and  average 
enlarged  spleen,  225.  (5)  The  fever  rate  and  index,  226.  (6)  The 
constantly-sick  rate  and  index,  229.     (7)  Malarial  death-rates,  230. 

(8)  Random  sampling,  230.  (9)  Variation  of  the  malaria  index 
according  to  age,  235.  (10)  Determination  of  the  inoculation  rate, 
239.     (11)  Practical  conclusions,  242. 

32.  The  Mortality  and  Cost  of  Malaria,  246.    Difficulties,  246.    Case 

mortality,  247.  Malarial  death-rate,  248.  Meldrum's  law,  250. 
Cost  of  malaria,  252. 

CHAPTER   VI.— PREVENTION 

33.  List  of  the  Possible  Preventive  Measures,  254. 

34.  Protection  against  the  Bites  of  Mosquitos,  257.    (i)  Portable  bed- 

nets,  257.  (2)  Portable  mosquito-proof  rooms,  260.  (3)  Fixed 
mosquito-proofrooms,  260.  (4)  Mosquito  proofing  of  windows  and 
doors,  261.  (5)  Mosquito  proofing  of  verandas,  262.  (6)  Pro- 
tection for  the  hands  and  feet,  263.  (7)  Medicinal  protectives, 
263.  (8)  Constant  movement,  264.  (9)  Fans  and  punkas,  264. 
(10)  Some  results,  264. 

35.  Mosquito  Reduction,  265.     (i)  Destruction  of  adults  by  hand,  265. 

(2)  Fumigation,  266.  (3)  Introduction  of  natural  enemies,  267. 
(4)  Destruction  of  larvae,  270.  (5)  The  screening  of  breeding 
waters,  272.  (6)  Dealing  with  breeding-holes,  273.  (7)  Training 
the  banks  of  streams,  rivers,  and  lakes,  275.    (8)  Major  works,  277. 

(9)  Trees,  279.     (10)  Houses,  280. 

36.  Prevention  by  Treatment,    281.     Treatment  of  the   sick,    282. 

Quinine  prophylaxis,  282.     Segregation,  285. 

37.  Selection  of  Measures  for  Personal  and  Domestic  Prophylaxis, 

287.  (i)  Self-protection  of  Europeans  in  the  tropics,  287.  (2) 
Domestic  precautions,  290.  (3)  Troops  on  service,  291.  (4)  Ships, 
292.  (5)  Hospitals  and  asylums,  292.  (6)  Barracks,  293.  (7) 
Prisons,  294.     (8)  Schools,  294.     (9)  General  rules,  294. 

38.  General  Sanitary  Axioms,  295. 


CONTENTS    IN    DETAIL  667 

Section 

39.  Selection  of  Measures  for  Public  Prevention,  296.    Comparison 

of  the  various  measures,  296. 

40.  Conduct  of  the  Campaig-n,  313.    (i)  First  steps,  313.    (2)  Appoint- 

ment of  a  directory,  314.  (3)  Anti-malaria  leagues,  315.  (4) 
Legislation,  316.  (5)  The  preliminary  malaria  survey,  317.  (6) 
Measures  in  schools,  319.  (7)  Measures  on  estates,  factories,  etc., 
320.  (8)  Other  quinine  distribution,  321.  (9)  Appointment  and 
instruction  of  moustiquiers,  323.  (10)  Malaria  gangs  for  minor 
works,  324.  (11)  Local  offices,  325.  (12)  Major  works,  325.  (13) 
The  annual  malaria  report,  327.    (14)  Cost,  328.    (15)  Remarks,  329. 


CHAPTER   VII.— SPECIAL   CONTRIBUTIONS 

41.  Anti-malaria  Work  in  the  United  States,  by  Professor  L.  0. 

Howard,  332.  Center  Island,  Long  Island,  California,  Staten 
Island,  333.  Brooklyn,  Worcester,  334.  Staten  Island,  336. 
Newport,  339.  New  Jersey,  340.  New  Orleans,  San  Antonio,  341. 
Cost,  343.     References,  344. 

42.  Malaria  Prevention   on  the  Isthmus  of  Panama,  by  Colonel 

W.  C.  Gorgas,  346.  Drainage,  347.  Brush  and  grass  cutting, 
348.  Oiling,  larvicide,  prophylactic  quinine,  screening,  349.  Kill- 
ing mosquitos  in  quarters,  cost,  350.     Notes  by  R.  Ross,  351. 

43.  Anti-malarial  Work  on  the  Isthmus  of  Panama— Technics,  by 

Chief  Sanitary  Inspector  J.  A.  Le  Prince,  353.  Surface 
ditches,  353.  Sub-drainage,  354.  Larvicide,  356.  Cotton  waste, 
357.     Detection  of  larvae,  destruction  of  adults,  359.     Results,  363. 

44.  Malaria  in  the  West  Indies,  by  Sir  Rubert  Boyee,  369.     Grenada, 

370.  St  Vincent,  371.  St  Lucia,  372.  Trinidad,  372.  British 
Guiana,  373.  Barbados,  374.  The  Bahamas,  374.  Jamaica,  375. 
British  Honduras,  375. 

45.  Malaria  in  Jamaica,  by  Dr  W.  T.  Prout,  376.    General  malarial 

death-  and  sick-rates,  377.  The  spleen  rate  379.  Anti-malarial 
measures,  380. 

46.  Malaria  in  the  Amazon  Region  and  the  Protection  of  Ships,  by 

Dr  H.  Wolferstan  Thomas,  582.  Iquitos  382.  Manaos,  383. 
Para,  384.     Protection  of  ships,  386. 

47.  Prophylaxis  of  Malaria  in  Central  and  Southern  Brazil,  by  Dr 

Oswaldo  G.  Cruz,  390.  The  first  prophylactic  formula,  391.  The 
second  prophylactic  formula,  391.  The  third  prophylactic  formula, 
393.     The  fourth  prophylactic  formula,  395.     References,  398. 

48.  Malaria   in  Spain,  by  Dr  Ian  Maedonald,  399.    History,  399. 

Mosquitos,  401.     Rio  Tinto,  404. 


668  CONTENTS    IN    DETAIL 

Section 

49.  The  Campaign  against  Malaria  in  Italy,  by  Professor  Angelo 

Celli,  406.  (i)  The  principles  of  epidemiology,  408.  (2)  The 
measures  for  combating  malarial  epidemics,  411.  (3)  Legislation 
concerning  malaria,  422.  (4)  Contribution  to  the  organisation  of 
the  campaign  against  malaria,  424.  (5)  General  results,  425.  (6) 
Conclusion,  429. 

50.  Anti-malaria  Measures  in  Greece,  by  Professor  Dr  C.  Savas. 

432.  (i)  Prevalence  of  malaria,  432.  (2)  Propagation  of  scientific 
knowledge,  434.  (3)  The  State  quinine,  437.  (4)  Marathon,  440. 
(5)  Laurium,  448.     (6)  Athens,  449. 

51.  The  Prevention  of  Malaria  in  German  Possessions,  by  Professor 

Dr  C.  Schilling,  451.  Various  localities,  451.  Kameruns,  469. 
German  South  West  Africa,  472.  South  Seas,  473.  Conclu- 
sions, 473. 

52.  Campagnes  Antipaludiques  en  Territoire,  Frangais,  by  Dr  Ed. 

Sergent,  475.  Algeria,  475.  Tunis,  489.  Corsica,  490.  French 
colonies,  492. 

53.  Mosquito   Reduction  in  Egypt,    by   H.  C.    Ross,    496.    General 

considerations,  496.  Ismaiha,  499.  Port  Said,  522.  Heluan,  525. 
Conclusions,  527. 

54.  The   Campaign   at   Khartoum,  by   Dr  Andrew  Balfour,    530. 

Mosquitos,  530.  Methods,  532.  Regulations  regarding  steamers> 
535.     Introduction  offish,  536.     Results,  540. 

55.  Malaria  in  South  Africa,  by  Dr  L.  Bostock,    543.     Komatipoort, 

544.  Portuguese  East  Africa,  546.  Mosquitos,  547.  Report  by 
C.  W.  Howard  on  mosquitos,  548. 

56.  Epidemic  of  Malaria  in  Durban,  1905-1907,  by  Dr  P.  Murison, 

549.     Description,  549.     Measures,  550.     Present  position,  551. 

57.  The  Prevention  of  Malaria  in  the  Federated  Malay  States,  by 

Dr  Malcolm  Watson  (abstract),  554.  (i)  Towns,  554.  Results, 
556.  (2)  District,  558.  Conclusions,  558.  Effect  of  roads,  effect 
of  jungle,  introduction  of  coolies,  quinine  prevention  compared 
with  drainage,  560. 

58.  Prevention  of  Malaria  in  Fromosa,  by  Dr  T.  Takaki,  563.    Pre- 

valence, mosquitos,  563.  Preventive  measures,  results,  565, 
Cost,  566. 

59.  Notes  on  Some  Other  Works,  by  Professor  R.  Ross,  568.    India, 

568.     Hongkong,  573.     Candia,  575. 

60.  The  Prevention  of  Malaria  in  War,  by  Colonel  C.  H.  Melville, 

577.     (i)  History,  577.     (2)  Practical  measures,  586. 

61.  The  Prevention  of  Malaria  among  Troops  under  Peace   Con- 

ditions, by  Major  C.  E.  P.  Fowler,  600.  Statistics,  600.  Larval 
destruction,  505.  Quinine,  607.  Protection,  611.  Segregation,  613. 
Quinine,  614. 


CONTENTS    IN    DETAIL  669 


ADDENDA 

Section 

62.  Suggested  Terminology  for  the  Phenomena  of  Cytogenesis,  621. 

63.  Notes  on  the  Malaria-beaping  Anophelines,  622.    (i)  Complete  list 

of  suspected  Anophelines  with  synonyms,  622.  (2)  Notes  on  the 
incriminated  Anophelines,  627. 

64.  Examples  of  Legislation,  636. 

65.  Notes,    638.     (i)   The   Thick-film    process,   638.      (2)     Enumerative 

methods,  639.  (3)  Some  results,  640.  (4)  Recent  work  of  S.  T. 
Darling  and  E.  H.  Ross,  641.  (5)  Three  more  mosquito  inocu- 
lations, 642.  (6)  The  attitude  of  Anophelines,  642.  (7)  Counting 
of  breeding-places.  (8)  M.  rossii.  (9)  Cost  of  malaria  in  India. 
(10)  Professor  Karl  Pearson  and  Mr  H.  Waite  confirm  result  of 
section  28,  643. 


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